Edit count of the user (user_editcount) | null |
Name of the user account (user_name) | '2600:8800:3000:2CF6:5CDD:B467:BD68:5F0' |
Age of the user account (user_age) | 0 |
Groups (including implicit) the user is in (user_groups) | [
0 => '*'
] |
Rights that the user has (user_rights) | [
0 => 'createaccount',
1 => 'read',
2 => 'edit',
3 => 'createtalk',
4 => 'writeapi',
5 => 'viewmywatchlist',
6 => 'editmywatchlist',
7 => 'viewmyprivateinfo',
8 => 'editmyprivateinfo',
9 => 'editmyoptions',
10 => 'abusefilter-log-detail',
11 => 'urlshortener-create-url',
12 => 'centralauth-merge',
13 => 'abusefilter-view',
14 => 'abusefilter-log',
15 => 'vipsscaler-test'
] |
Whether the user is editing from mobile app (user_app) | false |
Whether or not a user is editing through the mobile interface (user_mobile) | true |
Page ID (page_id) | 18016 |
Page namespace (page_namespace) | 0 |
Page title without namespace (page_title) | 'Lisp (programming language)' |
Full page title (page_prefixedtitle) | 'Lisp (programming language)' |
Edit protection level of the page (page_restrictions_edit) | [] |
Last ten users to contribute to the page (page_recent_contributors) | [
0 => 'GreenWeasel11',
1 => 'Landonrules',
2 => '2604:2000:1382:197:B07A:1BD:8D3E:DDA9',
3 => 'BHGbot',
4 => 'M.Bitton',
5 => '2601:585:8201:4D80:147D:51A4:827F:A029',
6 => 'InternetArchiveBot',
7 => 'Cheeseball701',
8 => '2409:4043:29F:C02:9132:5B19:2F46:8F8E',
9 => 'DannyS712'
] |
Page age in seconds (page_age) | 593964502 |
Action (action) | 'edit' |
Edit summary/reason (summary) | '' |
Old content model (old_content_model) | 'wikitext' |
New content model (new_content_model) | 'wikitext' |
Old page wikitext, before the edit (old_wikitext) | '{{redirect|LISP|the Internet protocol|Locator/Identifier Separation Protocol|the Japanese [[girl group]]|Lisp (group)|the speech impediment|Lisp}}
{{short description|Programming language family}}
{{Infobox programming language
| name = Lisp
| logo = Lisplogo.png
| paradigm = [[multi-paradigm programming language|Multi-paradigm]]: [[functional programming|functional]], [[procedural programming|procedural]], [[Reflection (computer programming)|reflective]], [[metaprogramming|meta]]
| released = {{Start date and age|1958}}
| designer = [[John McCarthy (computer scientist)|John McCarthy]]
| developer = [[Steve Russell (computer scientist)|Steve Russell]], Timothy P. Hart, and Mike Levin
| latest release version =
| latest release date =
| turing-complete = Yes
| typing = [[Dynamic typing|Dynamic]], [[Strong and weak typing|strong]]
| implementations =
| dialects = {{startflatlist}}
*[[Arc (programming language)|Arc]]
*[[AutoLISP]]
*[[Clojure]]
*[[Common Lisp]]
*[[Emacs Lisp]]
*[[EuLisp]]
*[[Franz Lisp]]
*[[Hy]]
*[[Interlisp]]
*[[ISLISP]]
*[[LeLisp]]
*[[LFE (programming language)|LFE]]
*[[Maclisp]]
*[[MDL (programming language)|MDL]]
*[[newLISP]]
*[[NIL (programming language)|NIL]]
*[[Picolisp]]
*[[Portable Standard Lisp]]
*[[Racket (programming language)|Racket]]
*[[RPL (programming language)|RPL]]
*[[Scheme (programming language)|Scheme]]
*[[Cadence SKILL|SKILL]]
*[[Spice Lisp]]
*[[T (programming language)|T]]
*[[Zetalisp]]
{{endflatlist}}
| influenced by = [[Information Processing Language|IPL]]
| influenced = {{startflatlist}}
*[[CLIPS]]
*[[CLU (programming language)|CLU]]
*[[COWSEL]]
*[[Dylan (programming language)|Dylan]]
*[[Elixir (programming language)|Elixir]]
*[[Forth (programming language)|Forth]]
*[[Haskell (programming language)|Haskell]]
*[[Io (programming language)|Io]]
*[[Ioke (programming language)|Ioke]]
*[[JavaScript]]
*[[Julia (programming language)|Julia]]<ref name="Julia">{{cite web |url=http://julia.readthedocs.org/en/latest/manual/introduction/ |title=Introduction |work=The Julia Manual |publisher=Read the Docs |accessdate=2016-12-10 |url-status=dead |archiveurl=https://web.archive.org/web/20160408134008/http://julia.readthedocs.org/en/latest/manual/introduction/ |archivedate=2016-04-08 }}</ref>
*[[Logo (programming language)|Logo]]
*[[Lua (programming language)|Lua]]
*[[ML (programming language)|ML]]
*[[Nim (programming language)|Nim]]
*[[Nu (programming language)|Nu]]
*[[OPS5]]
*[[Perl]]
*[[POP-2]]/[[POP-11|11]]
*[[Python (programming language)|Python]]
*[[R (programming language)|R]]
*[[Rebol]]
*[[Ruby (programming language)|Ruby]]
*[[Scala (programming language)|Scala]]
*[[Swift (programming language)|Swift]]
*[[Smalltalk]]
*[[Tcl]]
*[[Wolfram Language]]<ref name="Wolfram">{{cite web |url=https://www.wolfram.com/language/faq/ |title=Wolfram Language Q&A |publisher=Wolfram Research |accessdate=2016-12-10}}</ref>{{endflatlist}}
}}
'''Lisp''' (historically '''LISP''') is a family of [[programming language]]s with a long history and a distinctive, fully [[parenthesized]] [[Polish notation#Computer programming|prefix notation]].<ref>
{{cite book
| title = Milestones in computer science and information technology
| author = Edwin D. Reilly
| publisher = Greenwood Publishing Group
| year = 2003
| isbn = 978-1-57356-521-9
| pages = 156–157
| url = https://books.google.com/books?id=JTYPKxug49IC&pg=PA157
}}</ref>
Originally specified in 1958, Lisp is the second-oldest [[high-level programming language]] in widespread use today. Only [[Fortran]] is older, by one year.<ref>{{cite web|url=http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|archive-url=https://web.archive.org/web/20010727170154/http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|url-status=dead|archive-date=2001-07-27|quote=Lisp is a survivor, having been in use for about a quarter of a century. Among the active programming languages only Fortran has had a longer life.|title=SICP: Foreword}}</ref><ref>{{cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|title=Conclusions|access-date=2014-06-04|archive-url=https://web.archive.org/web/20140403021353/http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|archive-date=2014-04-03|url-status=dead}}</ref> Lisp has changed since its early days, and many [[Programming language dialect|dialects]] have existed over its history. Today, the best-known general-purpose Lisp dialects are [[Racket (programming language)|Racket]], [[Common Lisp]], [[Scheme (programming language)|Scheme]] and [[Clojure]].
Lisp was originally created as a practical [[mathematical notation]] for [[computer program]]s, influenced by the notation of [[Alonzo Church]]'s [[lambda calculus]]. It quickly became the favored programming language for [[artificial intelligence]] (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in [[computer science]], including [[tree (data structure)|tree data structures]], [[garbage collection (computer science)|automatic storage management]], [[dynamic typing]], [[Conditional (computer programming)|conditionals]], [[higher-order function]]s, [[recursion (computer science)|recursion]], the [[Self-hosting (compilers)|self-hosting]] [[compiler]],<ref name="Graham">{{cite web |title=Revenge of the Nerds |author=Paul Graham |url=http://www.paulgraham.com/icad.html |accessdate=2013-03-14}}</ref> and the [[read–eval–print loop]].<ref>{{Cite book|url=http://www.informit.com/articles/article.aspx?p=1671639&seqNum=3|title=Influential Programming Languages, Part 4: Lisp|last=Chisnall|first=David|date=2011-01-12}}</ref>
The name ''LISP'' derives from "LISt Processor".<ref name=ArtOfLisp>{{cite book|last1=Jones|first1=Robin|last2=Maynard|first2=Clive|last3=Stewart|first3=Ian|title=The Art of Lisp Programming|date=December 6, 2012|publisher=Springer Science & Business Media|isbn=9781447117193|page=2}}</ref> [[Linked list]]s are one of Lisp's major [[data structure]]s, and Lisp [[source code]] is made of lists. Thus, Lisp programs can manipulate source code as a data structure, giving rise to the [[macro (computer science)|macro]] systems that allow programmers to create new syntax or new [[domain-specific language]]s embedded in Lisp.
The interchangeability of code and data gives Lisp its instantly recognizable syntax. All program code is written as ''[[s-expression]]s'', or parenthesized lists. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function {{Lisp2|f}} that takes three arguments would be called as {{Lisp2|(f arg1 arg2 arg3)}}.
==History==
{{Multiple image|image1 = John McCarthy Stanford.jpg|footer = [[John McCarthy (computer scientist)|John McCarthy]] (top) and [[Steve Russell (computer scientist)|Steve Russell]]|image2 = Steve Russell.jpg|direction = vertical}}
[[John McCarthy (computer scientist)|John McCarthy]] developed Lisp in 1958 while he was at the [[Massachusetts Institute of Technology]] (MIT). McCarthy published its design in a paper in ''[[Communications of the ACM]]'' in 1960, entitled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I".<ref name="MCCARTHY">{{cite web| title=Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I| author=John McCarthy| url=http://www-formal.stanford.edu/jmc/recursive.html| accessdate=2006-10-13| archive-url=https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html| archive-date=2013-10-04| url-status=dead}}</ref> He showed that with a few simple operators and a notation for anonymous functions borrowed from Church, one can build a [[Turing completeness|Turing-complete]] language for algorithms.
[[Information Processing Language]] was the first AI language, from 1955 or 1956, and already included many of the concepts, such as list-processing and recursion, which came to be used in Lisp.
McCarthy's original notation used bracketed "[[M-expression]]s" that would be translated into [[S-expression]]s. As an example, the M-expression {{Lisp2|car[cons[A,B]]}} is equivalent to the S-expression {{Lisp2|(car (cons A B))}}. Once Lisp was implemented, programmers rapidly chose to use S-expressions, and M-expressions were abandoned. M-expressions surfaced again with short-lived attempts of [[MLisp]]<ref name="SMITH">{{cite web| title=MLISP Users Manual| author=David Canfield Smith | url=http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf | accessdate=2006-10-13}}</ref> by [[Horace Enea]] and [[CGOL]] by [[Vaughan Pratt]].
Lisp was first implemented by [[Steve Russell (computer scientist)|Steve Russell]] on an [[IBM 704]] computer using [[punched card]]s.<ref>{{Cite web|url=http://jmc.stanford.edu/articles/lisp/lisp.pdf|title=History of Lisp: Artificial Intelligence Laboratory|author=John McCarthy|date=12 February 1979}}</ref> Russell had read McCarthy's paper and realized (to McCarthy's surprise) that the Lisp ''eval'' function could be implemented in [[machine code]].<ref>According to what reported by [[Paul Graham (computer programmer)|Paul Graham]] in ''[[Hackers & Painters]]'', p. 185, McCarthy said: "Steve Russell said, look, why don't I program this ''eval'' ... and I said to him, ho, ho, you're confusing theory with practice, this ''eval'' is intended for reading, not for computing. But he went ahead and did it. That is, he compiled the ''eval'' in my paper into [[IBM 704]] machine code, fixing [[Software bug|bug]], and then advertised this as a Lisp interpreter, which it certainly was. So at that point Lisp had essentially the form that it has today ..."</ref> The result was a working Lisp interpreter which could be used to run Lisp programs, or more properly, "evaluate Lisp expressions".
Two [[assembly language macros]] for the [[IBM 704]] became the primitive operations for decomposing lists: [[car and cdr|{{Lisp2|car}}]] (''Contents of the Address part of Register'' number) and [[car and cdr|{{Lisp2|cdr}}]] (''Contents of the Decrement part of Register'' number),<ref name="PREHISTORY">{{cite web| title=LISP prehistory - Summer 1956 through Summer 1958| author=John McCarthy | url=http://www-formal.stanford.edu/jmc/history/lisp/node2.html | accessdate=2010-03-14}}</ref> where "register" is used to refer to [[Processor register|registers]] of the computer's [[central processing unit]] (CPU). Lisp dialects still use {{Lisp2|car}} and {{Lisp2|cdr}} ({{IPAc-en|k|ɑːr}} and {{IPAc-en|ˈ|k|ʊ|d|ər}}) for the operations that return the first item in a list and the rest of the list, respectively.
The first complete Lisp compiler, written in Lisp, was implemented in 1962 by Tim Hart and Mike Levin at MIT.<ref name="LEVIN">{{cite web| title=AI Memo 39-The new compiler| author=Tim Hart and Mike Levin| url=ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf| accessdate=2019-03-18}}</ref> This compiler introduced the Lisp model of incremental compilation, in which compiled and interpreted functions can intermix freely. The language used in Hart and Levin's memo is much closer to modern Lisp style than McCarthy's earlier code.
The first [[Garbage collection (computer science)|garbage collection]] routines were developed by MIT graduate student [[Daniel Edwards (programmer)|Daniel Edwards]].<ref name="1.5 manual" />
During the 1980s and 1990s, a great effort was made to unify the work on new Lisp dialects (mostly successors to [[Maclisp]] such as [[ZetaLisp]] and NIL (New Implementation of Lisp) into a single language. The new language, [[Common Lisp]], was somewhat compatible with the dialects it replaced (the book ''[[Common Lisp the Language]]'' notes the compatibility of various constructs). In 1994, [[ANSI]] published the Common Lisp standard, "ANSI X3.226-1994 Information Technology Programming Language Common Lisp".
=== Timeline ===
{{Lisp}}
===Connection to artificial intelligence===
Since inception, Lisp was closely connected with the [[artificial intelligence]] research community, especially on [[PDP-10]]<ref>The 36-bit word size of the [[PDP-6]]/[[PDP-10]] was influenced by the usefulness of having two Lisp 18-bit pointers in a single word. {{cite newsgroup | quote = The PDP-6 project started in early 1963, as a 24-bit machine. It grew to 36 bits for LISP, a design goal. | url = http://groups.google.com/group/alt.folklore.computers/browse_thread/thread/6e5602ce733d0ec/17597705ae289112 | title = The History of TOPS or Life in the Fast ACs | newsgroup = alt.folklore.computers |message-id= 84950@tut.cis.ohio-state.edu | date = 18 October 1990 | author = Peter J. Hurley}}</ref> systems. Lisp was used as the implementation of the programming language [[Planner programming language|Micro Planner]], which was used in the famous AI system [[SHRDLU]]. In the 1970s, as AI research spawned commercial offshoots, the performance of existing Lisp systems became a growing issue.{{Citation needed|date=March 2010}}
===Genealogy and variants===
Over its sixty-year history, Lisp has spawned many variations on the core theme of an S-expression language. Moreover, each given dialect may have several implementations—for instance, there are more than a dozen implementations of [[Common Lisp]].
Differences between dialects may be quite visible—for instance, Common Lisp uses the keyword <code>defun</code> to name a function, but Scheme uses <code>define</code>.<ref>Common Lisp: <code>(defun f (x) x)</code><br/>Scheme: <code>(define f (lambda (x) x))</code> or <code>(define (f x) x)</code></ref> Within a dialect that is standardized, however, conforming implementations support the same core language, but with different extensions and libraries.
====Historically significant dialects====
[[File:LISP machine.jpg|thumb|right|A [[Lisp machine]] in the [[MIT Museum]]]]
[[File:4.3 BSD UWisc VAX Emulation Lisp Manual.png|thumb|[[4.3BSD|4.3 BSD]] from the [[University of Wisconsin]], displaying the [[man page]] for [[Franz Lisp]]]]
*LISP 1<ref>{{Cite journal
|last=McCarthy
|first=J.
|author-link=John McCarthy (computer scientist)
|last2=Brayton
|first2=R.
|author2-link=Robert Brayton (computer scientist)
|last3=Edwards
|first3=D.
|author3-link=Daniel Edwards (programmer)
|last4=Fox
|first4=P.
|author4-link=Phyllis Fox
|last5=Hodes
|first5=L.
|author5-link=Louis Hodes
|last6=Luckham
|first6=D.
|author6-link=David Luckham
|last7=Maling
|first7=K.
|author7-link=Klim Maling (programmer)
|last8=Park
|first8=D.
|author8-link=David Park (computer scientist)
|last9=Russell
|first9=S.
|author9-link=Steve Russell (computer scientist)
|title=LISP I Programmers Manual
|place=[[Boston]], [[Massachusetts]]
|publisher=Artificial Intelligence Group, [[M.I.T. Computation Center]] and [[Research Laboratory of Electronics at MIT|Research Laboratory]]
|date=March 1960
|url=http://history.siam.org/sup/Fox_1960_LISP.pdf
|archiveurl=https://web.archive.org/web/20100717111134/http://history.siam.org/sup/Fox_1960_LISP.pdf
|archivedate=2010-07-17
|url-status=dead
}} Accessed May 11, 2010.</ref> – First implementation.
*LISP 1.5<ref name="1.5 manual">{{Cite book | url = https://archive.org/details/lisp15programmer00john | title = LISP 1.5 Programmer's Manual | publisher = [[MIT Press]] | first1 = John | last1 = McCarthy | first2 = Paul W. | last2 = Abrahams | first3 = Daniel J. | last3 = Edwards | first4 = Timothy P. | last4 = Hart | first5 = Michael I. | last5 = Levin | isbn = 0-262-13011-4 | origyear = 1962 | edition = 2nd | year = 1985 | url-access = registration }}</ref> – First widely distributed version, developed by McCarthy and others at MIT. So named because it contained several improvements on the original "LISP 1" interpreter, but was not a major restructuring as the planned [[LISP 2]] would be.
*[[Stanford LISP]] 1.6<ref>{{Cite book| url = http://www.softwarepreservation.org/projects/LISP/stanford/SAILON-28.6.pdf | format = PDF | title = Stanford LISP 1.6 Manual | first1 = Lynn H. | last1 = Quam | first2 = Whitfield | last2 = Diffle}}</ref> – This was a successor to LISP 1.5 developed at the [[Stanford AI Lab]], and widely distributed to [[PDP-10]] systems running the [[TOPS-10]] operating system. It was rendered obsolete by Maclisp and InterLisp.
*[[Maclisp|MACLISP]]<ref>{{cite web| url = http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt | title = Maclisp Reference Manual | date = March 3, 1979 | archiveurl = https://web.archive.org/web/20071214064433/http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt | archivedate = 2007-12-14}}</ref> – developed for MIT's [[Project MAC]], MACLISP is a direct descendant of LISP 1.5. It ran on the PDP-10 and [[Multics]] systems. MACLISP would later come to be called Maclisp, and is often referred to as MacLisp. The "MAC" in MACLISP is related neither to Apple's [[Macintosh]] nor to [[John McCarthy (computer scientist)|McCarthy]].
*[[Interlisp]]<ref>{{Cite book | url = http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf | format = PDF | title = InterLisp Reference Manual | first = Warren | last = Teitelman | year = 1974 | access-date = 2006-08-19 | archive-url = https://web.archive.org/web/20060602134835/http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf | archive-date = 2006-06-02 | url-status = dead }}</ref> – developed at [[BBN Technologies]] for PDP-10 systems running the [[TENEX (operating system)|TENEX operating system]], later adopted as a "West coast" Lisp for the Xerox Lisp machines as [[InterLisp-D]]. A small version called "InterLISP 65" was published for the [[MOS 6502|6502]]-based [[Atari 8-bit family]] computer line. For quite some time, Maclisp and InterLisp were strong competitors.
*[[Franz Lisp]] – originally a [[University of California, Berkeley]] project; later developed by Franz Inc. The name is a humorous deformation of the name "[[Franz Liszt]]", and does not refer to [[Allegro Common Lisp]], the dialect of Common Lisp sold by Franz Inc., in more recent years.
*[[XLISP]], which [[AutoLISP]] was based on.
*[[Standard Lisp]] and [[Portable Standard Lisp]] were widely used and ported, especially with the Computer Algebra System REDUCE.
*[[ZetaLisp]], also termed Lisp Machine Lisp – used on the [[Lisp machine]]s, direct descendant of Maclisp. ZetaLisp had a big influence on Common Lisp.
*[[LeLisp]] is a French Lisp dialect. One of the first [[Graphical user interface builder|Interface Builders]] (called SOS Interface<ref>[https://hal.archives-ouvertes.fr/file/index/docid/70041/filename/RT-0126.pdf Outils de generation d’interfaces : etat de l’art et classification by H. El Mrabet]</ref>) was written in LeLisp.
*[[Scheme (programming language)|Scheme]] (1975).<ref>ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
*[[Common Lisp]] (1984), as described by ''[[Common Lisp the Language]]'' – a consolidation of several divergent attempts (ZetaLisp, [[Spice Lisp]], [[NIL (programming language)|NIL]], and [[S-1 Lisp]]) to create successor dialects<ref>{{Cite book| chapterurl = https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node6.html | title = Common Lisp the Language | edition = 2nd | chapter = Purpose | first = Guy L., Jr. | last = Steele| isbn = 0-13-152414-3}}</ref> to Maclisp, with substantive influences from the Scheme dialect as well. This version of Common Lisp was available for wide-ranging platforms and was accepted by many as a [[de facto standard]]<ref>{{cite web| url = https://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/faq-doc-13.html | title = History: Where did Lisp come from? | work = FAQ: Lisp Frequently Asked Questions 2/7 | date = 20 February 1996 | first1 = Mark | last1 = Kantrowitz | first2 = Barry | last2 = Margolin}}</ref> until the publication of ANSI Common Lisp (ANSI X3.226-1994). Among the most widespread sub-dialects of Common Lisp are [[Steel Bank Common Lisp]] (SBCL), CMU Common Lisp (CMU-CL), Clozure OpenMCL (not to be confused with Clojure!), GNU CLisp, and later versions of Franz Lisp; all of them adhere to the later ANSI CL standard (see below).
*[[Dylan (programming language)|Dylan]] was in its first version a mix of Scheme with the Common Lisp Object System.
*[[EuLisp]] – attempt to develop a new efficient and cleaned-up Lisp.
*[[ISLISP]] – attempt to develop a new efficient and cleaned-up Lisp. Standardized as ISO/IEC 13816:1997<ref>{{cite web|url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22987 |title=ISO/IEC 13816:1997 |publisher=Iso.org |date=2007-10-01 |accessdate=2013-11-15}}</ref> and later revised as ISO/IEC 13816:2007:<ref>{{cite web|url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44338 |title=ISO/IEC 13816:2007 |publisher=Iso.org |date=2013-10-30 |accessdate=2013-11-15}}</ref> ''Information technology – Programming languages, their environments and system software interfaces – Programming language ISLISP''.
*IEEE [[Scheme (programming language)|Scheme]] – IEEE standard, 1178–1990 (R1995)
*ANSI [[Common Lisp]] – an [[American National Standards Institute]] (ANSI) [[Standardization|standard]] for Common Lisp, created by subcommittee [[X3J13]], chartered<ref>{{cite web| url = http://www.nhplace.com/kent/CL/x3j13-86-020.html | title = X3J13 Charter}}</ref> to begin with ''Common Lisp: The Language'' as a base document and to work through a public [[Consensus decision-making|consensus]] process to find solutions to shared issues of [[Portability (software)|portability]] of programs and [[Computer compatibility|compatibility]] of Common Lisp implementations. Although formally an ANSI standard, the implementation, sale, use, and influence of ANSI Common Lisp has been and continues to be seen worldwide.
*[[ACL2]] or "A Computational Logic for Applicative Common Lisp", an applicative (side-effect free) variant of Common LISP. ACL2 is both a programming language which can model computer systems, and a tool to help proving properties of those models.
*[[Clojure]], a recent dialect of Lisp which compiles to the [[Java virtual machine]] and has a particular focus on [[Concurrency (computer science)|concurrency]].
*[[Game Oriented Assembly Lisp]] (or GOAL) is a video game programming language developed by Andy Gavin and the [[Jak and Daxter]] team at [[Naughty Dog]]. It was written using Allegro Common Lisp and used in the development of the entire [[Jak and Daxter|Jak and Daxter series of games]].
===2000 to present===
After having declined somewhat in the 1990s, Lisp has experienced a resurgence of interest after 2000. Most new activity has been focused around implementations of [[Common Lisp]], [[Scheme (programming language)|Scheme]], [[Emacs Lisp]], [[Clojure]], and [[Racket (programming language)|Racket]], and includes development of new portable libraries and applications.
Many new Lisp programmers were inspired by writers such as [[Paul Graham (computer programmer)|Paul Graham]] and [[Eric S. Raymond]] to pursue a language others considered antiquated. New Lisp programmers often describe the language as an eye-opening experience and claim to be substantially more productive than in other languages.<ref>{{cite web |title=The Road To Lisp Survey |url=http://wiki.alu.org/The_Road_To_Lisp_Survey |accessdate=2006-10-13 |archive-url=https://web.archive.org/web/20061004031130/http://wiki.alu.org/The_Road_To_Lisp_Survey |archive-date=2006-10-04 |url-status=dead }}</ref> This increase in awareness may be contrasted to the "[[AI winter]]" and Lisp's brief gain in the mid-1990s.<ref>{{cite web |url=http://www.faqs.org/docs/artu/ch14s05.html |title=Trends for the Future |publisher=Faqs.org |accessdate=2013-11-15}}</ref>
Dan Weinreb lists in his survey of Common Lisp implementations<ref>{{cite web|last=Weinreb|first=Daniel|title=Common Lisp Implementations: A Survey|url=http://common-lisp.net/~dlw/LispSurvey.html|accessdate=4 April 2012|archive-url=https://web.archive.org/web/20120421181340/http://common-lisp.net/~dlw/LispSurvey.html#|archive-date=2012-04-21|url-status=dead}}</ref> eleven actively maintained Common Lisp implementations. Scieneer Common Lisp is a new commercial implementation forked from CMUCL with a first release in 2002.
The [[open-source-software movement|open source]] community has created new supporting infrastructure: [[CLiki]] is a wiki that collects Common Lisp related information, the [[Common Lisp directory]] lists resources, #lisp is a popular IRC channel and allows the sharing and commenting of code snippets (with support by [[lisppaste]], an [[IRC bot]] written in Lisp), [[Planet Lisp]] collects the contents of various Lisp-related blogs, on [[LispForum]] users discuss Lisp topics, [[Lispjobs]] is a service for announcing job offers and there is a weekly news service, ''[[Weekly Lisp News]]''. ''Common-lisp.net'' is a hosting site for open source Common Lisp projects. [[Quicklisp]] is a library manager for Common Lisp.
Fifty years of Lisp (1958–2008) was celebrated at LISP50@OOPSLA.<ref>{{cite web|url=http://www.lisp50.org/ |title=LISP50@OOPSLA |publisher=Lisp50.org |accessdate=2013-11-15}}</ref> There are regular local user meetings in Boston, Vancouver, and Hamburg. Other events include the European Common Lisp Meeting, the European Lisp Symposium and an International Lisp Conference.
The Scheme community actively maintains [[Scheme (programming language)#Implementations|over twenty implementations]]. Several significant new implementations (Chicken, Gambit, Gauche, Ikarus, Larceny, Ypsilon) have been developed in the 2000s (decade). The Revised<sup>5</sup> Report on the Algorithmic Language Scheme<ref>[http://www.schemers.org/Documents/Standards/R5RS/ Documents: Standards: R5RS]. schemers.org (2012-01-11). Retrieved on 2013-07-17.</ref> standard of Scheme was widely accepted in the Scheme community. The [[Scheme Requests for Implementation]] process has created a lot of quasi standard libraries and extensions for Scheme. User communities of individual Scheme implementations continue to grow. A new language standardization process was started in 2003 and led to the R<sup>6</sup>RS Scheme standard in 2007. Academic use of Scheme for teaching computer science seems to have declined somewhat. Some universities are no longer using Scheme in their computer science introductory courses;<ref>{{cite news|url=http://cemerick.com/2009/03/24/why-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program/|title=Why MIT now uses python instead of scheme for its undergraduate CS program|date=March 24, 2009|work=cemerick.com|accessdate=November 10, 2013}}</ref><ref>{{cite news|url=http://mitadmissions.org/blogs/entry/the_end_of_an_era_1|title=The End of an Era|first=Evan|last=Broder|date=January 8, 2008|work=mitadmissions.org|accessdate=November 10, 2013}}</ref> MIT now uses [[Python (programming language)|Python]] instead of Scheme for its undergraduate [[computer science]] program and MITx massive open online course.<ref name="MITEECS-Python">{{cite web |title=MIT EECS Undergraduate Programs |url=https://www.eecs.mit.edu/academics-admissions/undergraduate-programs |website=www.eecs.mit.edu |publisher=MIT Electrical Engineering & Computer Science |accessdate=31 December 2018}}</ref><ref name="MITx-Phyton">{{cite web |title=MITx introductory Python course hits 1.2 million enrollments |url=https://www.eecs.mit.edu/news-events/announcements/mitx-introductory-python-course-hits-12-million-enrollments |website=MIT EECS |publisher=MIT Electrical Engineering & Computer Science |accessdate=31 December 2018}}</ref>
There are several new dialects of Lisp: [[Arc (programming language)|Arc]], [[Hy]], [[Nu (programming language)|Nu]], [[Liskell]], and [[LFE (programming language)|LFE]] (Lisp Flavored Erlang). The parser for [[Julia (programming language)|Julia]] is implemented in Femtolisp, a dialect of [[Scheme (programming language)|Scheme]] (Julia is inspired by Scheme, which in turn is a Lisp dialect).
In October 2019, Paul Graham released [http://paulgraham.com/bel.html a specification for Bel], "a new dialect of Lisp."
==Major dialects==
[[Common Lisp]] and [[Scheme (programming language)|Scheme]] represent two major streams of Lisp development. These languages embody significantly different design choices.
[[Common Lisp]] is a successor to [[Maclisp]]. The primary influences were [[Lisp Machine Lisp]], Maclisp, [[NIL (programming language)|NIL]], [[S-1 Lisp]], [[Spice Lisp]], and Scheme.<ref>Chapter 1.1.2, History, ANSI CL Standard</ref> It has many of the features of Lisp Machine Lisp (a large Lisp dialect used to program [[Lisp Machine]]s), but was designed to be efficiently implementable on any personal computer or workstation. Common Lisp is a general-purpose programming language and thus has a large language standard including many built-in data types, functions, macros and other language elements, and an object system ([[Common Lisp Object System]]). Common Lisp also borrowed certain features from Scheme such as [[lexical scoping]] and [[lexical closure]]s. Common Lisp implementations are available for targeting different platforms such as the [[LLVM]],<ref>[https://www.cliki.net/Clasp] Clasp is a Common Lisp implementation that interoperates with C++ and uses LLVM for [[just-in-time compilation]] (JIT) to native code.</ref> the [[Java virtual machine]],<ref>[https://common-lisp.net/project/armedbear/] "Armed Bear Common Lisp (ABCL) is a full implementation of the Common Lisp language featuring both an interpreter and a compiler, running in the JVM"</ref>
x86-64, PowerPC, Alpha, ARM, Motorola 68000, and MIPS,<ref>[https://common-lisp.net/~dlw/LispSurvey.html] {{Webarchive|url=https://web.archive.org/web/20180622083812/https://common-lisp.net/~dlw/LispSurvey.html# |date=2018-06-22 }} Common Lisp Implementations: A Survey</ref> and operating systems such as Windows, macOS, Linux, Solaris, FreeBSD, NetBSD, OpenBSD, Dragonfly BSD, and Heroku.<ref>[https://www.cliki.net/Common+Lisp+implementation] Comparison of actively developed Common Lisp implementations</ref>
Scheme is a statically scoped and properly tail-recursive dialect of the Lisp programming language invented by [[Guy L. Steele, Jr.]] and [[Gerald Jay Sussman]]. It was designed to have exceptionally clear and simple semantics and few different ways to form expressions. Designed about a decade earlier than Common Lisp, [[Scheme (programming language)|Scheme]] is a more minimalist design. It has a much smaller set of standard features but with certain implementation features (such as [[tail-call optimization]] and full [[continuation]]s) not specified in Common Lisp. A wide variety of programming paradigms, including imperative, functional, and message passing styles, find convenient expression in Scheme. Scheme continues to evolve with a series of standards (Revised<sup>n</sup> Report on the Algorithmic Language Scheme) and a series of [[Scheme Requests for Implementation]].
[[Clojure]] is a recent dialect of Lisp that targets mainly the [[Java virtual machine]], and the [[Common Language Runtime]] (CLR), the [[Python (programming language)|Python]] VM, the Ruby VM [[YARV]], and compiling to [[JavaScript]]. It is designed to be a pragmatic general-purpose language. Clojure draws considerable influences from [[Haskell (programming language)|Haskell]] and places a very strong emphasis on immutability.<ref name="clojure-immutability">[http://www.infoq.com/articles/in-depth-look-clojure-collections An In-Depth Look at Clojure Collections], Retrieved 2012-06-24</ref> Clojure provides access to Java frameworks and libraries, with optional type hints and [[type inference]], so that calls to Java can avoid reflection and enable fast primitive operations. Clojure is not designed to be backwards compatible with other Lisp dialects.<ref>{{cite web |title=Clojure rational |url=https://clojure.org/about/rationale |accessdate=27 August 2019 |quote=Clojure is a Lisp not constrained by backwards compatibility}}</ref>
Further, Lisp dialects are used as [[scripting language]]s in many applications, with the best-known being [[Emacs Lisp]] in the [[Emacs]] editor, [[AutoLISP]] and later [[Visual Lisp]] in [[AutoCAD]], Nyquist in [[Audacity (audio editor)|Audacity]], Scheme in [[LilyPond]]. The potential small size of a useful Scheme interpreter makes it particularly popular for embedded scripting. Examples include [[SIOD]] and [[TinyScheme]], both of which have been successfully embedded in the [[GIMP]] image processor under the generic name "Script-fu".<ref name="script-fu">[http://www.gimp.org/docs/script-fu-update.html Script-fu In GIMP 2.4], Retrieved 2009-10-29</ref> LIBREP, a Lisp interpreter by John Harper originally based on the [[Emacs Lisp]] language, has been embedded in the [[Sawfish (window manager)|Sawfish]] [[window manager]].<ref name="librep">[http://sawfish.wikia.com/wiki/Librep librep] at Sawfish Wikia, retrieved 2009-10-29</ref>
===Standardized dialects===
Lisp has officially standardized dialects: [[Scheme (programming language)#R6RS|R6RS Scheme]], [[Scheme (programming language)#R7RS|R7RS Scheme]], IEEE Scheme,<ref>{{cite web |url=https://standards.ieee.org/standard/1178-1990.html |website=IEEE 1178-1990 - IEEE Standard for the Scheme Programming Language |accessdate=27 August 2019 |title=IEEE Scheme}}</ref> [[ANSI Common Lisp]] and ISO [[ISLISP]].
==Language innovations==
Lisp was the first language where the structure of program code is represented faithfully and directly in a standard data structure—a quality much later dubbed "[[homoiconicity]]". Thus, Lisp functions can be manipulated, altered or even created within a Lisp program without lower-level manipulations. This is generally considered one of the main advantages of the language with regard to its expressive power, and makes the language suitable for syntactic macros and [[metacircular evaluation]].
A conditional using an ''[[if–then–else]]'' syntax was invented by McCarthy in a Fortran context. He proposed its inclusion in [[ALGOL]], but it was not made part of the [[Algol 58]] specification. For Lisp, McCarthy used the more general ''cond''-structure.<ref>{{cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node2.html|title=LISP prehistory - Summer 1956 through Summer 1958.|quote=I invented conditional expressions in connection with a set of chess legal move routines I wrote in FORTRAN for the IBM 704 at M.I.T. during 1957–58 ... A paper defining conditional expressions and proposing their use in Algol was sent to the Communications of the ACM but was arbitrarily demoted to a letter to the editor, because it was very short.}}</ref> [[Algol 60]] took up ''if–then–else'' and popularized it.
Lisp deeply influenced [[Alan Kay]], the leader of the research team that developed [[Smalltalk]] at [[Xerox PARC]]; and in turn Lisp was influenced by Smalltalk, with later dialects adopting object-oriented programming features (inheritance classes, encapsulating instances, message passing, etc.) in the 1970s. The [[Flavors (programming language)|Flavors]] object system introduced the concept of [[multiple inheritance]] and the [[mixin]]. The [[Common Lisp Object System]] provides multiple inheritance, multimethods with [[multiple dispatch]], and first-class [[generic functions]], yielding a flexible and powerful form of [[dynamic dispatch]]. It has served as the template for many subsequent Lisp (including [[Scheme (programming language)|Scheme]]) object systems, which are often implemented via a [[Metaobject#Metaobject Protocol|metaobject protocol]], a [[Reflection (computer science)|reflective]] [[Metacircular evaluator|metacircular design]] in which the object system is defined in terms of itself: Lisp was only the second language after Smalltalk (and is still one of the very few languages) to possess such a metaobject system. Many years later, Alan Kay suggested that as a result of the confluence of these features, only Smalltalk and Lisp could be regarded as properly conceived object-oriented programming systems.<ref>{{cite web|date=2003-07-23|url=http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en|title=Meaning of 'Object-Oriented Programming' According to Dr. Alan Kay|quote=I didn't understand the monster LISP idea of tangible metalanguage then, but got kind of close with ideas about extensible languages ... The second phase of this was to finally understand LISP and then using this understanding to make much nicer and smaller and more powerful and more late bound understructures ... OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them.}}</ref>
Lisp introduced the concept of [[Garbage collection (computer science)|automatic garbage collection]], in which the system walks the [[Heap (memory management)|heap]] looking for unused memory. Progress in modern sophisticated garbage collection algorithms such as generational garbage collection was stimulated by its use in Lisp.<ref>{{citation |last=Lieberman |first=Henry |last2=Hewitt |first2=Carl |title=A Real-Time Garbage Collector Based on the Lifetimes of Objects |url=http://web.media.mit.edu/~lieber/Lieberary/GC/Realtime/Realtime.html |journal=Communications of the ACM |volume=26 |issue=6 |date=June 1983 |pages=419–429 |doi=10.1145/358141.358147|citeseerx=10.1.1.4.8633 }}</ref>
[[Edsger W. Dijkstra]] in his 1972 [[Turing Award]] lecture said,
:"With a few very basic principles at its foundation, it [LISP] has shown a remarkable stability. Besides that, LISP has been the carrier for a considerable number of in a sense our most sophisticated computer applications. LISP has jokingly been described as “the most intelligent way to misuse a computer”. I think that description a great compliment because it transmits the full flavour of liberation: it has assisted a number of our most gifted fellow humans in thinking previously impossible thoughts."<ref>{{citation|url=http://www.cs.utexas.edu/~EWD/transcriptions/EWD03xx/EWD340.html|author=Edsger W. Dijkstra|year=1972|title=The Humble Programmer (EWD 340)}} (ACM Turing Award lecture).</ref>
Largely because of its resource requirements with respect to early computing hardware (including early microprocessors), Lisp did not become as popular outside of the [[AI]] community as [[Fortran]] and the [[ALGOL]]-descended [[C (programming language)|C]] language. Because of its suitability to complex and dynamic applications, Lisp is enjoying some resurgence of popular interest in the 2010s.<ref>{{cite web|url=https://www.linkedin.com/pulse/look-clojure-lisp-resurgence-todd-towles|title=A Look at Clojure and the Lisp Resurgence}}</ref>
==Syntax and semantics==
:'''''Note''': This article's examples are written in [[Common Lisp]] (though most are also valid in [[Scheme (programming language)|Scheme]]).''
===Symbolic expressions (S-expressions)===
Lisp is an [[expression oriented language]]. Unlike most other languages, no distinction is made between "expressions" and [[Statement (programming)|"statements"]];{{dubious|date=April 2013}}<!-- (progn ...), (setq ...). There is no syntactic distinction, but sequential evaluation is there. --> all code and data are written as expressions. When an expression is ''evaluated'', it produces a value (in Common Lisp, possibly multiple values), which can then be embedded into other expressions. Each value can be any data type.
McCarthy's 1958 paper introduced two types of syntax: ''Symbolic expressions'' ([[S-expression]]s, sexps), which mirror the internal representation of code and data; and ''Meta expressions'' ([[M-expression]]s), which express functions of S-expressions. M-expressions never found favor, and almost all Lisps today use S-expressions to manipulate both code and data.
The use of parentheses is Lisp's most immediately obvious difference from other programming language families. As a result, students have long given Lisp nicknames such as ''Lost In Stupid Parentheses'', or ''Lots of Irritating Superfluous Parentheses''.<ref name="LEVIN2">{{cite web| title=The Jargon File - Lisp| url=http://www.catb.org/~esr/jargon/html/L/LISP.html| accessdate=2006-10-13}}</ref><!-- Add NO more nicknames. People can check the Jargon File for them. --> However, the S-expression syntax is also responsible for much of Lisp's power: the syntax is extremely regular, which facilitates manipulation by computer. However, the syntax of Lisp is not limited to traditional parentheses notation. It can be extended to include alternative notations. For example, XMLisp is a Common Lisp extension that employs the [[Metaobject#Metaobject protocol|metaobject protocol]] to integrate S-expressions with the Extensible Markup Language ([[XML]]).
The reliance on expressions gives the language great flexibility. Because Lisp [[function (programming)|functions]] are written as lists, they can be processed exactly like data. This allows easy writing of programs which manipulate other programs ([[metaprogramming]]). Many Lisp dialects exploit this feature using macro systems, which enables extension of the language almost without limit.
===Lists===
A Lisp list is written with its elements separated by [[Whitespace character|whitespace]], and surrounded by parentheses. For example, {{Lisp2|(1 2 foo)}} is a list whose elements are the three ''atoms'' {{Lisp2|1}}, {{Lisp2|2}}, and [[foo|{{Lisp2|foo}}]]. These values are implicitly typed: they are respectively two integers and a Lisp-specific data type called a "symbol", and do not have to be declared as such.
The empty list {{Lisp2|()}} is also represented as the special atom {{Lisp2|nil}}. This is the only entity in Lisp which is both an atom and a list.
Expressions are written as lists, using [[Polish notation|prefix notation]]. The first element in the list is the name of a function, the name of a macro, a lambda expression or the name of a "special operator" (see below). The remainder of the list are the arguments. For example, the function {{Lisp2|list}} returns its arguments as a list, so the expression
<syntaxhighlight lang="Lisp">
(list 1 2 (quote foo))
</syntaxhighlight>
evaluates to the list {{Lisp2|(1 2 foo)}}. The "quote" before the [[foo|{{Lisp2|foo}}]] in the preceding example is a "special operator" which returns its argument without evaluating it. Any unquoted expressions are recursively evaluated before the enclosing expression is evaluated. For example,
<syntaxhighlight lang="Lisp">
(list 1 2 (list 3 4))
</syntaxhighlight>
evaluates to the list {{Lisp2|(1 2 (3 4))}}. Note that the third argument is a list; lists can be nested.
===Operators===
Arithmetic operators are treated similarly. The expression
<syntaxhighlight lang="Lisp">
(+ 1 2 3 4)
</syntaxhighlight>
evaluates to 10. The equivalent under [[infix notation]] would be "{{Lisp2|1 + 2 + 3 + 4}}".
Lisp has no notion of operators as implemented in Algol-derived languages. Arithmetic operators in Lisp are [[variadic function]]s (or ''n-ary''), able to take any number of arguments. A C-style '++' increment operator is sometimes implemented under the name <tt>incf</tt> giving syntax
<syntaxhighlight lang="Lisp">
(incf x)
</syntaxhighlight>
equivalent to <tt>(setq x (+ x 1))</tt>, returning the new value of <tt>x</tt>.
"Special operators" (sometimes called "special forms") provide Lisp's control structure. For example, the special operator {{Lisp2|if}} takes three arguments. If the first argument is non-nil, it evaluates to the second argument; otherwise, it evaluates to the third argument. Thus, the expression
<syntaxhighlight lang="Lisp">
(if nil
(list 1 2 "foo")
(list 3 4 "bar"))
</syntaxhighlight>
evaluates to {{Lisp2|(3 4 "bar")}}. Of course, this would be more useful if a non-trivial expression had been substituted in place of {{Lisp2|nil}}.
Lisp also provides logical operators '''and''', '''or''' and '''not'''. The '''and''' and '''or''' operators do [[short circuit evaluation]] and will return their first nil and non-nil argument respectively.
<syntaxhighlight lang="Lisp">
(or (and "zero" nil "never") "James" 'task 'time)
</syntaxhighlight>
will evaluate to "James".
===Lambda expressions and function definition===
Another special operator, {{Lisp2|lambda}}, is used to bind variables to values which are then evaluated within an expression. This operator is also used to create functions: the arguments to {{Lisp2|lambda}} are a list of arguments, and the expression or expressions to which the function evaluates (the returned value is the value of the last expression that is evaluated). The expression
<syntaxhighlight lang="Lisp">
(lambda (arg) (+ arg 1))
</syntaxhighlight>
evaluates to a function that, when applied, takes one argument, binds it to {{Lisp2|arg}} and returns the number one greater than that argument. Lambda expressions are treated no differently from named functions; they are invoked the same way. Therefore, the expression
<syntaxhighlight lang="Lisp">
((lambda (arg) (+ arg 1)) 5)
</syntaxhighlight>
evaluates to {{Lisp2|6}}. Here, we're doing a function application: we execute the [[anonymous function]] by passing to it the value 5.
Named functions are created by storing a lambda expression in a symbol using the [[defun]] macro.
<syntaxhighlight lang="Lisp">
(defun foo (a b c d) (+ a b c d))
</syntaxhighlight>
{{Lisp2|(defun f (a) b...)}} defines a new function named {{Lisp2|f}} in the global environment. It is conceptually similar to the expression:
<syntaxhighlight lang="Lisp">
(setf (fdefinition 'f) #'(lambda (a) (block f b...)))
</syntaxhighlight>
===Atoms===
In the original '''LISP''' there were two fundamental [[data type]]s: atoms and lists. A list was a finite ordered sequence of elements, where each element is either an atom or a list, and an atom was a [[number]] or a symbol. A symbol was essentially a unique named item, written as an [[alphanumeric]] string in [[source code]], and used either as a variable name or as a data item in [[symbolic processing]]. For example, the list {{Lisp2|(FOO (BAR 1) 2)}} contains three elements: the symbol {{Lisp2|FOO}}, the list {{Lisp2|(BAR 1)}}, and the number 2.
The essential difference between atoms and lists was that atoms were immutable and unique. Two atoms that appeared in different places in source code but were written in exactly the same way represented the same object,{{Citation needed|date=November 2008}} whereas each list was a separate object that could be altered independently of other lists and could be distinguished from other lists by comparison operators.
As more data types were introduced in later Lisp dialects, and [[programming style]]s evolved, the concept of an atom lost importance.{{Citation needed|date=November 2008}} Many dialects still retained the predicate ''atom'' for [[legacy compatibility]],{{Citation needed|date=November 2008}} defining it true for any object which is not a cons.
===Conses and lists===
{{Main|Cons}}
[[File:Cons-cells.svg|thumb|right|300px|Box-and-[[pointer (computer programming)|pointer]] diagram for the list (42 69 613)]]
A Lisp list is implemented as a [[singly linked list]].<ref name=SebestaLanguages>{{cite book |last1=Sebesta |first1=Robert W. |title=Concepts of Programming Languages |chapter="2.4 Functional Programming: LISP";"6.9 List Types";"15.4 The First Functional Programming Language: LISP" |date=2012 |publisher=Addison-Wesley |location=Boston, MA, USA |isbn=978-0-13-139531-2 |pages=47–52;281–284;677–680 |edition=10th |url=https://www.pearson.com/us/higher-education/product/Sebesta-Concepts-of-Programming-Languages-10th-Edition/9780131395312.html |language=en |format=print}}</ref> Each cell of this list is called a ''cons'' (in Scheme, a ''pair''), and is composed of two [[pointer (computer programming)|pointer]]s, called the ''car'' and ''cdr''. These are respectively equivalent to the {{Lisp2|data}} and {{Lisp2|next}} fields discussed in the article ''[[linked list]]''.
Of the many data structures that can be built out of cons cells, one of the most basic is called a ''proper list''. A proper list is either the special {{Lisp2|nil}} (empty list) symbol, or a cons in which the {{Lisp2|car}} points to a datum (which may be another cons structure, such as a list), and the {{Lisp2|cdr}} points to another proper list.
If a given cons is taken to be the head of a linked list, then its car points to the first element of the list, and its cdr points to the rest of the list. For this reason, the {{Lisp2|car}} and {{Lisp2|cdr}} functions are also called {{Lisp2|first}} and {{Lisp2|rest}} when referring to conses which are part of a linked list (rather than, say, a tree).
Thus, a Lisp list is not an atomic object, as an instance of a container class in C++ or Java would be. A list is nothing more than an aggregate of linked conses. A variable which refers to a given list is simply a pointer to the first cons in the list. Traversal of a list can be done by ''cdring down'' the list; that is, taking successive cdrs to visit each cons of the list; or by using any of several [[higher-order function]]s to map a function over a list.
Because conses and lists are so universal in Lisp systems, it is a common misconception that they are Lisp's only data structures. In fact, all but the most simplistic Lisps have other data structures, such as vectors ([[Array data type|arrays]]), hash tables, structures, and so forth.
====S-expressions represent lists====
Parenthesized S-expressions represent linked list structures. There are several ways to represent the same list as an S-expression. A cons can be written in ''dotted-pair notation'' as {{Lisp2|(a . b)}}, where {{Lisp2|a}} is the car and {{Lisp2|b}} the cdr. A longer proper list might be written {{Lisp2|(a . (b . (c . (d . nil))))}} in dotted-pair notation. This is conventionally abbreviated as {{Lisp2|(a b c d)}} in ''list notation''. An improper list<ref>NB: a so-called "dotted list" is only one kind of "improper list". The other kind is the "circular list" where the cons cells form a loop. Typically this is represented using #n=(...) to represent the target cons cell that will have multiple references, and #n# is used to refer to this cons. For instance, (#1=(a b) . #1#) would normally be printed as ((a b) a b) (without circular structure printing enabled), but makes the reuse of the cons cell clear. #1=(a . #1#) cannot normally be printed as it is circular, although (a...) is sometimes displayed, the CDR of the cons cell defined by #1= is itself.</ref> may be written in a combination of the two – as {{Lisp2|(a b c . d)}} for the list of three conses whose last cdr is {{Lisp2|d}} (i.e., the list {{Lisp2|(a . (b . (c . d)))}} in fully specified form).
====List-processing procedures====
Lisp provides many built-in procedures for accessing and controlling lists. Lists can be created directly with the {{Lisp2|list}} procedure, which takes any number of arguments, and returns the list of these arguments.
<syntaxhighlight lang="Lisp">
(list 1 2 'a 3)
;Output: (1 2 a 3)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(list 1 '(2 3) 4)
;Output: (1 (2 3) 4)
</syntaxhighlight>
Because of the way that lists are constructed from [[cons pair]]s, the {{Lisp2|cons}} procedure can be used to add an element to the front of a list. Note that the {{Lisp2|cons}} procedure is asymmetric in how it handles list arguments, because of how lists are constructed.
<syntaxhighlight lang="Lisp">
(cons 1 '(2 3))
;Output: (1 2 3)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(cons '(1 2) '(3 4))
;Output: ((1 2) 3 4)
</syntaxhighlight>
The {{Lisp2|append}} procedure appends two (or more) lists to one another. Because Lisp lists are linked lists, appending two lists has [[Big O notation|asymptotic time complexity]] <math>O(n)</math>
<syntaxhighlight lang="Lisp">
(append '(1 2) '(3 4))
;Output: (1 2 3 4)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(append '(1 2 3) '() '(a) '(5 6))
;Output: (1 2 3 a 5 6)
</syntaxhighlight>
====Shared structure====
Lisp lists, being simple linked lists, can share structure with one another. That is to say, two lists can have the same ''tail'', or final sequence of conses. For instance, after the execution of the following Common Lisp code:
<syntaxhighlight lang="Lisp">
(setf foo (list 'a 'b 'c))
(setf bar (cons 'x (cdr foo)))
</syntaxhighlight>
the lists {{Lisp2|foo}} and {{Lisp2|bar}} are {{Lisp2|(a b c)}} and {{Lisp2|(x b c)}} respectively. However, the tail {{Lisp2|(b c)}} is the same structure in both lists. It is not a copy; the cons cells pointing to {{Lisp2|b}} and {{Lisp2|c}} are in the same memory locations for both lists.
Sharing structure rather than copying can give a dramatic performance improvement. However, this technique can interact in undesired ways with functions that alter lists passed to them as arguments. Altering one list, such as by replacing the {{Lisp2|c}} with a {{Lisp2|goose}}, will affect the other:
<syntaxhighlight lang="Lisp">
(setf (third foo) 'goose)
</syntaxhighlight>
This changes {{Lisp2|foo}} to {{Lisp2|(a b goose)}}, but thereby also changes {{Lisp2|bar}} to {{Lisp2|(x b goose)}} – a possibly unexpected result. This can be a source of bugs, and functions which alter their arguments are documented as ''destructive'' for this very reason.
Aficionados of [[functional programming]] avoid destructive functions. In the Scheme dialect, which favors the functional style, the names of destructive functions are marked with a cautionary exclamation point, or "bang"—such as {{Lisp2|set-car!}} (read ''set car bang''), which replaces the car of a cons. In the Common Lisp dialect, destructive functions are commonplace; the equivalent of {{Lisp2|set-car!}} is named {{Lisp2|rplaca}} for "replace car." This function is rarely seen however as Common Lisp includes a special facility, {{Lisp2|setf}}, to make it easier to define and use destructive functions. A frequent style in Common Lisp is to write code functionally (without destructive calls) when prototyping, then to add destructive calls as an optimization where it is safe to do so.
===Self-evaluating forms and quoting===
Lisp evaluates expressions which are entered by the user. Symbols and lists evaluate to some other (usually, simpler) expression – for instance, a symbol evaluates to the value of the variable it names; {{Lisp2|(+ 2 3)}} evaluates to {{Lisp2|5}}. However, most other forms evaluate to themselves: if entering {{Lisp2|5}} into Lisp, it returns {{Lisp2|5}}.
Any expression can also be marked to prevent it from being evaluated (as is necessary for symbols and lists). This is the role of the {{Lisp2|quote}} special operator, or its abbreviation {{Lisp2|'}} (one quotation mark). For instance, usually if entering the symbol {{Lisp2|foo}}, it returns the value of the corresponding variable (or an error, if there is no such variable). To refer to the literal symbol, enter {{Lisp2|(quote foo)}} or, usually, {{Lisp2|'foo}}.
{{anchor|Backquote}}Both Common Lisp and Scheme also support the ''backquote'' operator (termed ''[[quasiquote]]'' in Scheme), entered with the {{Lisp2|`}} character ([[Grave accent#Use in programming|grave accent]]). This is almost the same as the plain quote, except it allows expressions to be evaluated and their values interpolated into a quoted list with the comma {{Lisp2|,}} ''unquote'' and comma-at {{Lisp2|,@}} ''splice'' operators. If the variable {{Lisp2|snue}} has the value {{Lisp2|(bar baz)}} then {{Lisp2|`(foo ,snue)}} evaluates to {{Lisp2|(foo (bar baz))}}, while {{Lisp2|`(foo ,@snue)}} evaluates to {{Lisp2|(foo bar baz)}}. The backquote is most often used in defining macro expansions.<ref>{{cite web|url=http://www.cs.washington.edu/education/courses/cse341/04wi/lectures/14-scheme-quote.html |title=CSE 341: Scheme: Quote, Quasiquote, and Metaprogramming |publisher=Cs.washington.edu |date=1999-02-22 |accessdate=2013-11-15}}</ref><ref>[http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf Quasiquotation in Lisp] {{Webarchive|url=https://web.archive.org/web/20130603114956/http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf |date=2013-06-03 }}, Alan Bawden</ref>
Self-evaluating forms and quoted forms are Lisp's equivalent of literals. It may be possible to modify the values of (mutable) literals in program code. For instance, if a function returns a quoted form, and the code that calls the function modifies the form, this may alter the behavior of the function on subsequent invocations.
<syntaxhighlight lang="lisp">
(defun should-be-constant ()
'(one two three))
(let ((stuff (should-be-constant)))
(setf (third stuff) 'bizarre)) ; bad!
(should-be-constant) ; returns (one two bizarre)
</syntaxhighlight>
Modifying a quoted form like this is generally considered bad style, and is defined by ANSI Common Lisp as erroneous (resulting in "undefined" behavior in compiled files, because the file-compiler can coalesce similar constants, put them in write-protected memory, etc.).
Lisp's formalization of quotation has been noted by [[Douglas Hofstadter]] (in ''[[Gödel, Escher, Bach]]'') and others as an example of the [[philosophy|philosophical]] idea of [[self-reference]].
===Scope and closure===
The Lisp family splits over the use of [[dynamic scoping|dynamic]] or [[static scoping|static]] (a.k.a. lexical) [[scope (programming)|scope]]. Clojure, Common Lisp and Scheme make use of static scoping by default, while [[newLISP]], [[Picolisp]] and the embedded languages in [[Emacs]] and [[AutoCAD]] use dynamic scoping. Since version 24.1, Emacs uses both dynamic and lexical scoping.
===List structure of program code; exploitation by macros and compilers===
A fundamental distinction between Lisp and other languages is that in Lisp, the textual representation of a program is simply a human-readable description of the same internal data structures (linked lists, symbols, number, characters, etc.) as would be used by the underlying Lisp system.
Lisp uses this to implement a very powerful macro system. Like other macro languages such as [[C (programming language)|C]], a macro returns code that can then be compiled. However, unlike C macros, the macros are Lisp functions and so can exploit the full power of Lisp.
Further, because Lisp code has the same structure as lists, macros can be built with any of the list-processing functions in the language. In short, anything that Lisp can do to a data structure, Lisp macros can do to code. In contrast, in most other languages, the parser's output is purely internal to the language implementation and cannot be manipulated by the programmer.
This feature makes it easy to develop ''efficient'' languages within languages. For example, the Common Lisp Object System can be implemented cleanly as a language extension using macros. This means that if an application needs a different inheritance mechanism, it can use a different object system. This is in stark contrast to most other languages; for example, Java does not support multiple inheritance and there is no reasonable way to add it.
In simplistic Lisp implementations, this list structure is directly [[interpreter (computing)|interpreted]] to run the program; a function is literally a piece of list structure which is traversed by the interpreter in executing it. However, most substantial Lisp systems also include a compiler. The compiler translates list structure into machine code or [[bytecode]] for execution. This code can run as fast as code compiled in conventional languages such as C.
Macros expand before the compilation step, and thus offer some interesting options. If a program needs a precomputed table, then a macro might create the table at compile time, so the compiler need only output the table and need not call code to create the table at run time. Some Lisp implementations even have a mechanism, <code>eval-when</code>, that allows code to be present during compile time (when a macro would need it), but not present in the emitted module.<ref>[https://www.gnu.org/software/emacs/manual/html_node/cl/Time-of-Evaluation.html Time of Evaluation - Common Lisp Extensions]. Gnu.org. Retrieved on 2013-07-17.</ref>
===Evaluation and the read–eval–print loop===
Lisp languages are often used with an interactive [[command line]], which may be combined with an [[integrated development environment]] (IDE). The user types in expressions at the command line, or directs the IDE to transmit them to the Lisp system. Lisp ''reads'' the entered expressions, ''evaluates'' them, and ''prints'' the result. For this reason, the Lisp command line is called a ''[[read–eval–print loop]]'' ([[REPL]]).
The basic operation of the REPL is as follows. This is a simplistic description which omits many elements of a real Lisp, such as quoting and macros.
The {{Lisp2|read}} function accepts textual S-expressions as input, and parses them into an internal data structure. For instance, if you type the text {{Lisp2|(+ 1 2)}} at the prompt, {{Lisp2|read}} translates this into a linked list with three elements: the symbol {{Lisp2|+}}, the number 1, and the number 2. It so happens that this list is also a valid piece of Lisp code; that is, it can be evaluated. This is because the car of the list names a function—the addition operation.
Note that a {{Lisp2|foo}} will be read as a single symbol. {{Lisp2|123}} will be read as the number one hundred and twenty-three. {{Lisp2|"123"}} will be read as the string "123".
The {{Lisp2|eval}} function evaluates the data, returning zero or more other Lisp data as a result. Evaluation does not have to mean interpretation; some Lisp systems compile every expression to native machine code. It is simple, however, to describe evaluation as interpretation: To evaluate a list whose car names a function, {{Lisp2|eval}} first evaluates each of the arguments given in its cdr, then applies the function to the arguments. In this case, the function is addition, and applying it to the argument list {{Lisp2|(1 2)}} yields the answer {{Lisp2|3}}. This is the result of the evaluation.
The symbol {{Lisp2|foo}} evaluates to the value of the symbol foo. Data like the string "123" evaluates to the same string. The list {{Lisp2|(quote (1 2 3))}} evaluates to the list (1 2 3).
It is the job of the {{Lisp2|print}} function to represent output to the user. For a simple result such as {{Lisp2|3}} this is trivial. An expression which evaluated to a piece of list structure would require that {{Lisp2|print}} traverse the list and print it out as an S-expression.
To implement a Lisp REPL, it is necessary only to implement these three functions and an infinite-loop function. (Naturally, the implementation of {{Lisp2|eval}} will be complex, since it must also implement all special operators like {{Lisp2|if}} or {{Lisp2|lambda}}.) This done, a basic REPL is one line of code: {{Lisp2|(loop (print (eval (read))))}}.
The Lisp REPL typically also provides input editing, an input history, error handling and an interface to the debugger.
Lisp is usually evaluated [[eager evaluation|eagerly]]. In [[Common Lisp]], arguments are evaluated in [[applicative order]] ('leftmost innermost'), while in [[Scheme programming language|Scheme]] order of arguments is undefined, leaving room for optimization by a compiler.
===Control structures===
Lisp originally had very few control structures, but many more were added during the language's evolution. (Lisp's original conditional operator, {{Lisp2|cond}}, is the precursor to later {{Lisp2|if-then-else}} structures.)
Programmers in the Scheme dialect often express loops using [[tail recursion]]. Scheme's commonality in academic computer science has led some students to believe that tail recursion is the only, or the most common, way to write iterations in Lisp, but this is incorrect. All oft-seen Lisp dialects have imperative-style iteration constructs, from Scheme's {{Lisp2|do}} loop to [[Common Lisp]]'s complex {{Lisp2|loop}} expressions. Moreover, the key issue that makes this an objective rather than subjective matter is that Scheme makes specific requirements for the handling of [[tail call]]s, and thus the reason that the use of tail recursion is generally encouraged for Scheme is that the practice is expressly supported by the language definition. By contrast, ANSI Common Lisp does not require<ref>[http://www.lispworks.com/documentation/HyperSpec/Body/03_bbc.htm 3.2.2.3 Semantic Constraints] in [http://www.lispworks.com/documentation/HyperSpec/Front/index.htm ''Common Lisp HyperSpec'']</ref> the optimization commonly termed a tail call elimination. Thus, the fact that tail recursive style as a casual replacement for the use of more traditional [[iteration]] constructs (such as {{Lisp2|do}}, {{Lisp2|dolist}} or {{Lisp2|loop}}) is discouraged<ref>4.3. Control Abstraction (Recursion vs. Iteration) in [http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf Tutorial on Good Lisp Programming Style] by [[Kent Pitman]] and [[Peter Norvig]], August, 1993.</ref> in Common Lisp is not just a matter of stylistic preference, but potentially one of efficiency (since an apparent tail call in Common Lisp may not compile as a simple [[Branch (computer science)|jump]]) and program correctness (since tail recursion may increase stack use in Common Lisp, risking [[stack overflow]]).
Some Lisp control structures are ''special operators'', equivalent to other languages' syntactic keywords. Expressions using these operators have the same surface appearance as function calls, but differ in that the arguments are not necessarily evaluated—or, in the case of an iteration expression, may be evaluated more than once.
In contrast to most other major programming languages, Lisp allows implementing control structures using the language. Several control structures are implemented as Lisp macros, and can even be macro-expanded by the programmer who wants to know how they work.
Both Common Lisp and Scheme have operators for non-local control flow. The differences in these operators are some of the deepest differences between the two dialects. Scheme supports ''re-entrant [[continuation]]s'' using the {{Lisp2|call/cc}} procedure, which allows a program to save (and later restore) a particular place in execution. Common Lisp does not support re-entrant continuations, but does support several ways of handling escape continuations.
Often, the same algorithm can be expressed in Lisp in either an imperative or a functional style. As noted above, Scheme tends to favor the functional style, using tail recursion and continuations to express control flow. However, imperative style is still quite possible. The style preferred by many Common Lisp programmers may seem more familiar to programmers used to structured languages such as C, while that preferred by Schemers more closely resembles pure-functional languages such as [[Haskell (programming language)|Haskell]].
Because of Lisp's early heritage in list processing, it has a wide array of higher-order functions relating to iteration over sequences. In many cases where an explicit loop would be needed in other languages (like a {{Lisp2|for}} loop in C) in Lisp the same task can be accomplished with a higher-order function. (The same is true of many functional programming languages.)
A good example is a function which in Scheme is called {{Lisp2|map}} and in Common Lisp is called {{Lisp2|mapcar}}. Given a function and one or more lists, {{Lisp2|mapcar}} applies the function successively to the lists' elements in order, collecting the results in a new list:
<syntaxhighlight lang="Lisp">
(mapcar #'+ '(1 2 3 4 5) '(10 20 30 40 50))
</syntaxhighlight>
This applies the {{Lisp2|+}} function to each corresponding pair of list elements, yielding the result {{Lisp2|(11 22 33 44 55)}}.
==Examples==
Here are examples of Common Lisp code.
The basic "[[Hello world]]" program:
<syntaxhighlight lang="Lisp">
(print "Hello world")
</syntaxhighlight>
Lisp syntax lends itself naturally to recursion. Mathematical problems such as the enumeration of recursively defined sets are simple to express in this notation.
Evaluate a number's [[factorial]]:
<syntaxhighlight lang="Lisp">
(defun factorial (n)
(if (= n 0) 1
(* n (factorial (- n 1)))))
</syntaxhighlight>
An alternative implementation takes less stack space than the previous version if the underlying Lisp system optimizes [[tail recursion]]:
<syntaxhighlight lang="Lisp">
(defun factorial (n &optional (acc 1))
(if (= n 0) acc
(factorial (- n 1) (* acc n))))
</syntaxhighlight>
Contrast with an iterative version which uses [[Common Lisp]]'s {{Lisp2|loop}} macro:
<syntaxhighlight lang="Lisp">
(defun factorial (n)
(loop for i from 1 to n
for fac = 1 then (* fac i)
finally (return fac)))
</syntaxhighlight>
The following function reverses a list. (Lisp's built-in ''reverse'' function does the same thing.)
<syntaxhighlight lang="Lisp">
(defun -reverse (list)
(let ((return-value '()))
(dolist (e list) (push e return-value))
return-value))
</syntaxhighlight>
==Object systems==
Various object systems and models have been built on top of, alongside, or into Lisp, including:
*The [[Common Lisp Object System]], CLOS, is an integral part of ANSI Common Lisp. CLOS descended from New Flavors and CommonLOOPS. ANSI Common Lisp was the first standardized object-oriented programming language (1994, ANSI X3J13).
*ObjectLisp<ref>pg 17 of Bobrow 1986</ref> or [[Object Lisp]], used by [[Lisp Machines Incorporated]] and early versions of Macintosh Common Lisp
*LOOPS (Lisp Object-Oriented Programming System) and the later [[CommonLOOPS]]
*[[Flavors (computer science)|Flavors]], built at [[Massachusetts Institute of Technology|MIT]], and its descendant New Flavors (developed by [[Symbolics]]).
*KR (short for Knowledge Representation), a [[Constraint satisfaction|constraint]]s-based object system developed to aid the writing of Garnet, a GUI library for [[Common Lisp]].
*[[Knowledge Engineering Environment]] (KEE) used an object system called UNITS and integrated it with an [[inference engine]]<ref>Veitch, p 108, 1988</ref> and a [[Truth maintenance systems|truth maintenance system]] (ATMS).
==See also==
* [[Self-modifying code]]
==References==
{{Reflist|30em}}
==Further reading==
{{Refbegin}}
*{{cite web
| last = McCarthy
| first = John
| authorlink =
| title = The implementation of Lisp
| work = History of Lisp
| publisher = Stanford University
| date = 1979-02-12
| url = http://www-formal.stanford.edu/jmc/history/lisp/node3.html
| doi =
| accessdate = 2008-10-17}}
*{{Cite conference
| first = Guy L.
| last = Steele, Jr.
| authorlink =
|author2=Richard P. Gabriel
| title = The evolution of Lisp
| conference = The second ACM SIGPLAN conference on History of programming languages
| pages = 231–270
| publisher = ACM
| year = 1993
| location = New York, NY
| url = http://www.dreamsongs.com/NewFiles/HOPL2-Uncut.pdf
| doi =
| id =
| isbn = 0-89791-570-4
| accessdate = 2008-10-17}}
*{{Cite book
| first = Jim
| last = Veitch
| author-link =
| author2-link =
| editor-last = Salus
| editor-first = Peter H
| editor2-last =
| editor2-first =
| contribution = A history and description of CLOS
| contribution-url =
| title = Handbook of programming languages
| volume = Volume IV, Functional and logic programming languages
| edition = first
| year = 1998
| pages = [https://archive.org/details/handbookofprogra0000unse/page/107 107–158]
| place = Indianapolis, IN
| publisher = Macmillan Technical Publishing
| url = https://archive.org/details/handbookofprogra0000unse/page/107
| doi =
| id =
| isbn = 1-57870-011-6
| postscript = <!--None-->
}}
*{{Cite book
|title= [[Structure and Interpretation of Computer Programs]]
|first= Harold
|last= Abelson
|author-link= Harold Abelson
|first2= Gerald Jay
|last2= Sussman
|author2-link= Gerald Jay Sussman
|first3= Julie
|last3= Sussman
|author3-link= Julie Sussman
|year= 1996
|edition= 2nd
|publisher= MIT Press
|isbn= 0-262-01153-0
|doi= }}
*[https://www.gnu.org/gnu/rms-lisp.html My Lisp Experiences and the Development of GNU Emacs], [[transcription (linguistics)|transcript]] of [[Richard Stallman]]'s speech, 28 October 2002, at the [[International Lisp Conference]]
*{{Cite book
|first= Paul
|last= Graham
|author-link= Paul Graham (computer programmer)
|title= [[Hackers & Painters| Hackers & Painters. Big Ideas from the Computer Age]]
|year= 2004
|publisher= O'Reilly
|isbn= 0-596-00662-4
|doi= }}
*{{Cite book
|editor-last= Berkeley
|editor-first= Edmund C.
|editor-link= Edmund Berkeley
|editor2-last= Bobrow
|editor2-first= Daniel G.
|editor2-link= Daniel G. Bobrow
|title= The Programming Language LISP: Its Operation and Applications
|url= http://www.softwarepreservation.org/projects/LISP/book/III_LispBook_Apr66.pdf
|date= March 1964
|publisher= MIT Press
|location= Cambridge, Massachusetts
|isbn=
|doi= }}
**Article largely based on the ''LISP - A Simple Introduction'' chapter: {{cite journal |last1=Berkeley |first1=Edmund C. |title=THE PROGRAMMING LANGUAGE LISP: AN INTRODUCTION AND APPRAISAL |journal=Computers and Automation |date=Sep 1964 |pages=[https://archive.org/details/bitsavers_computersA_6908895/page/n15 16]-23 |url=https://archive.org/details/bitsavers_computersA_6908895}}
*{{Cite book
|last= Weissman
|first= Clark
|title= LISP 1.5 Primer
|year= 1967
|url= http://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf
|publisher= Dickenson Publishing Company Inc.
|location= Belmont, California
|isbn=
|doi=}}
{{Refend}}
==External links==
{{Sister project links|wikt=Lisp|commons=Category:Lisp (programming language)|n=no|q=Lisp programming language|b=Subject:Lisp programming language|v=Topic:Lisp|s=Lambda Papers}}
;History
*[http://www-formal.stanford.edu/jmc/history/lisp/lisp.html History of Lisp] – [[John McCarthy (computer scientist)|John McCarthy]]'s history of 12 February 1979
*[https://web.archive.org/web/20050617031004/http://www8.informatik.uni-erlangen.de/html/lisp-enter.html Lisp History] – Herbert Stoyan's history compiled from the documents (acknowledged by McCarthy as more complete than his own, see: [http://www-formal.stanford.edu/jmc/history/ McCarthy's history links])
*[http://www.softwarepreservation.org/projects/LISP/ History of LISP at the Computer History Museum]
;Associations and meetings
*[http://www.alu.org/ Association of Lisp Users]
*[http://www.weitz.de/eclm2013/ European Common Lisp Meeting]
*[http://european-lisp-symposium.org/ European Lisp Symposium]
*[http://www.international-lisp-conference.org/ International Lisp Conference]
; Books and tutorials
*''[http://www.lisperati.com/casting.html Casting SPELs in Lisp]'', a comic-book style introductory tutorial
*''[http://paulgraham.com/onlisptext.html On Lisp]'', a free book by [[Paul Graham (computer programmer)|Paul Graham]]
*''[http://www.gigamonkeys.com/book/ Practical Common Lisp]'', freeware edition by Peter Seibel
* [http://leanpub.com/lispweb Lisp for the web]
* [http://landoflisp.com/ Land of Lisp]
* [http://letoverlambda.com/ Let over Lambda]
; Interviews
*[http://purl.umn.edu/107476 Oral history interview with John McCarthy] at [[Charles Babbage Institute]], University of Minnesota, Minneapolis. McCarthy discusses his role in the development of time-sharing at the Massachusetts Institute of Technology. He also describes his work in artificial intelligence (AI) funded by the Advanced Research Projects Agency, including logic-based AI (LISP) and robotics.
*[http://www.se-radio.net/2008/01/episode-84-dick-gabriel-on-lisp/ Interview] with [[Richard P. Gabriel]] (Podcast)
;Resources
*[http://www.cliki.net/ CLiki: the Common Lisp wiki]
*[https://web.archive.org/web/20160311102031/http://www.cl-user.net/asp/erw/sdataQIvH87hu8NU%24DM%3D%3D/sdataQo5Y-1Mh9urk The Common Lisp Directory] (via the [[Wayback Machine]]; archived from [https://web.archive.org/web/20080905110332/http://cl-user.net/ the original])
*[http://www.faqs.org/faqs/lisp-faq/ Lisp FAQ Index]
*[http://paste.lisp.org/ lisppaste]
*[http://planet.lisp.org/ Planet Lisp]
*[http://lispnews.wordpress.com/ Weekly Lisp News]
*{{Curlie|Computers/Programming/Languages/Lisp|Lisp}}
{{Lisp programming language}}
{{John McCarthy navbox}}
{{Programming languages}}
{{Authority control}}
{{DEFAULTSORT:Lisp Programming Language}}
[[Category:Lisp (programming language)| ]]
[[Category:Academic programming languages]]
[[Category:American inventions]]
[[Category:Articles with example Lisp code]]
[[Category:Dynamically typed programming languages]]
[[Category:Extensible syntax programming languages]]
[[Category:Functional languages]]
[[Category:Lisp programming language family| ]]
[[Category:Programming languages]]
[[Category:Programming languages created in 1958]]' |
New page wikitext, after the edit (new_wikitext) | '==History==
{{Multiple image|image1 = John McCarthy Stanford.jpg|footer = [[John McCarthy (computer scientist)|John McCarthy]] (top) and [[Steve Russell (computer scientist)|Steve Russell]]|image2 = Steve Russell.jpg|direction = vertical}}
[[John McCarthy (computer scientist)|John McCarthy]] developed Lisp in 1958 while he was at the [[Massachusetts Institute of Technology]] (MIT). McCarthy published its design in a paper in ''[[Communications of the ACM]]'' in 1960, entitled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I".<ref name="MCCARTHY">{{cite web| title=Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I| author=John McCarthy| url=http://www-formal.stanford.edu/jmc/recursive.html| accessdate=2006-10-13| archive-url=https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html| archive-date=2013-10-04| url-status=dead}}</ref> He showed that with a few simple operators and a notation for anonymous functions borrowed from Church, one can build a [[Turing completeness|Turing-complete]] language for algorithms.
[[Information Processing Language]] was the first AI language, from 1955 or 1956, and already included many of the concepts, such as list-processing and recursion, which came to be used in Lisp.
McCarthy's original notation used bracketed "[[M-expression]]s" that would be translated into [[S-expression]]s. As an example, the M-expression {{Lisp2|car[cons[A,B]]}} is equivalent to the S-expression {{Lisp2|(car (cons A B))}}. Once Lisp was implemented, programmers rapidly chose to use S-expressions, and M-expressions were abandoned. M-expressions surfaced again with short-lived attempts of [[MLisp]]<ref name="SMITH">{{cite web| title=MLISP Users Manual| author=David Canfield Smith | url=http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf | accessdate=2006-10-13}}</ref> by [[Horace Enea]] and [[CGOL]] by [[Vaughan Pratt]].
Lisp was first implemented by [[Steve Russell (computer scientist)|Steve Russell]] on an [[IBM 704]] computer using [[punched card]]s.<ref>{{Cite web|url=http://jmc.stanford.edu/articles/lisp/lisp.pdf|title=History of Lisp: Artificial Intelligence Laboratory|author=John McCarthy|date=12 February 1979}}</ref> Russell had read McCarthy's paper and realized (to McCarthy's surprise) that the Lisp ''eval'' function could be implemented in [[machine code]].<ref>According to what reported by [[Paul Graham (computer programmer)|Paul Graham]] in ''[[Hackers & Painters]]'', p. 185, McCarthy said: "Steve Russell said, look, why don't I program this ''eval'' ... and I said to him, ho, ho, you're confusing theory with practice, this ''eval'' is intended for reading, not for computing. But he went ahead and did it. That is, he compiled the ''eval'' in my paper into [[IBM 704]] machine code, fixing [[Software bug|bug]], and then advertised this as a Lisp interpreter, which it certainly was. So at that point Lisp had essentially the form that it has today ..."</ref> The result was a working Lisp interpreter which could be used to run Lisp programs, or more properly, "evaluate Lisp expressions".
Two [[assembly language macros]] for the [[IBM 704]] became the primitive operations for decomposing lists: [[car and cdr|{{Lisp2|car}}]] (''Contents of the Address part of Register'' number) and [[car and cdr|{{Lisp2|cdr}}]] (''Contents of the Decrement part of Register'' number),<ref name="PREHISTORY">{{cite web| title=LISP prehistory - Summer 1956 through Summer 1958| author=John McCarthy | url=http://www-formal.stanford.edu/jmc/history/lisp/node2.html | accessdate=2010-03-14}}</ref> where "register" is used to refer to [[Processor register|registers]] of the computer's [[central processing unit]] (CPU). Lisp dialects still use {{Lisp2|car}} and {{Lisp2|cdr}} ({{IPAc-en|k|ɑːr}} and {{IPAc-en|ˈ|k|ʊ|d|ər}}) for the operations that return the first item in a list and the rest of the list, respectively.
The first complete Lisp compiler, written in Lisp, was implemented in 1962 by Tim Hart and Mike Levin at MIT.<ref name="LEVIN">{{cite web| title=AI Memo 39-The new compiler| author=Tim Hart and Mike Levin| url=ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf| accessdate=2019-03-18}}</ref> This compiler introduced the Lisp model of incremental compilation, in which compiled and interpreted functions can intermix freely. The language used in Hart and Levin's memo is much closer to modern Lisp style than McCarthy's earlier code.
The first [[Garbage collection (computer science)|garbage collection]] routines were developed by MIT graduate student [[Daniel Edwards (programmer)|Daniel Edwards]].<ref name="1.5 manual" />
During the 1980s and 1990s, a great effort was made to unify the work on new Lisp dialects (mostly successors to [[Maclisp]] such as [[ZetaLisp]] and NIL (New Implementation of Lisp) into a single language. The new language, [[Common Lisp]], was somewhat compatible with the dialects it replaced (the book ''[[Common Lisp the Language]]'' notes the compatibility of various constructs). In 1994, [[ANSI]] published the Common Lisp standard, "ANSI X3.226-1994 Information Technology Programming Language Common Lisp".
=== Timeline ===
{{Lisp}}
===Connection to artificial intelligence===
Since inception, Lisp was closely connected with the [[artificial intelligence]] research community, especially on [[PDP-10]]<ref>The 36-bit word size of the [[PDP-6]]/[[PDP-10]] was influenced by the usefulness of having two Lisp 18-bit pointers in a single word. {{cite newsgroup | quote = The PDP-6 project started in early 1963, as a 24-bit machine. It grew to 36 bits for LISP, a design goal. | url = http://groups.google.com/group/alt.folklore.computers/browse_thread/thread/6e5602ce733d0ec/17597705ae289112 | title = The History of TOPS or Life in the Fast ACs | newsgroup = alt.folklore.computers |message-id= 84950@tut.cis.ohio-state.edu | date = 18 October 1990 | author = Peter J. Hurley}}</ref> systems. Lisp was used as the implementation of the programming language [[Planner programming language|Micro Planner]], which was used in the famous AI system [[SHRDLU]]. In the 1970s, as AI research spawned commercial offshoots, the performance of existing Lisp systems became a growing issue.{{Citation needed|date=March 2010}}
===Genealogy and variants===
Over its sixty-year history, Lisp has spawned many variations on the core theme of an S-expression language. Moreover, each given dialect may have several implementations—for instance, there are more than a dozen implementations of [[Common Lisp]].
Differences between dialects may be quite visible—for instance, Common Lisp uses the keyword <code>defun</code> to name a function, but Scheme uses <code>define</code>.<ref>Common Lisp: <code>(defun f (x) x)</code><br/>Scheme: <code>(define f (lambda (x) x))</code> or <code>(define (f x) x)</code></ref> Within a dialect that is standardized, however, conforming implementations support the same core language, but with different extensions and libraries.
====Historically significant dialects====
[[File:LISP machine.jpg|thumb|right|A [[Lisp machine]] in the [[MIT Museum]]]]
[[File:4.3 BSD UWisc VAX Emulation Lisp Manual.png|thumb|[[4.3BSD|4.3 BSD]] from the [[University of Wisconsin]], displaying the [[man page]] for [[Franz Lisp]]]]
*LISP 1<ref>{{Cite journal
|last=McCarthy
|first=J.
|author-link=John McCarthy (computer scientist)
|last2=Brayton
|first2=R.
|author2-link=Robert Brayton (computer scientist)
|last3=Edwards
|first3=D.
|author3-link=Daniel Edwards (programmer)
|last4=Fox
|first4=P.
|author4-link=Phyllis Fox
|last5=Hodes
|first5=L.
|author5-link=Louis Hodes
|last6=Luckham
|first6=D.
|author6-link=David Luckham
|last7=Maling
|first7=K.
|author7-link=Klim Maling (programmer)
|last8=Park
|first8=D.
|author8-link=David Park (computer scientist)
|last9=Russell
|first9=S.
|author9-link=Steve Russell (computer scientist)
|title=LISP I Programmers Manual
|place=[[Boston]], [[Massachusetts]]
|publisher=Artificial Intelligence Group, [[M.I.T. Computation Center]] and [[Research Laboratory of Electronics at MIT|Research Laboratory]]
|date=March 1960
|url=http://history.siam.org/sup/Fox_1960_LISP.pdf
|archiveurl=https://web.archive.org/web/20100717111134/http://history.siam.org/sup/Fox_1960_LISP.pdf
|archivedate=2010-07-17
|url-status=dead
}} Accessed May 11, 2010.</ref> – First implementation.
*LISP 1.5<ref name="1.5 manual">{{Cite book | url = https://archive.org/details/lisp15programmer00john | title = LISP 1.5 Programmer's Manual | publisher = [[MIT Press]] | first1 = John | last1 = McCarthy | first2 = Paul W. | last2 = Abrahams | first3 = Daniel J. | last3 = Edwards | first4 = Timothy P. | last4 = Hart | first5 = Michael I. | last5 = Levin | isbn = 0-262-13011-4 | origyear = 1962 | edition = 2nd | year = 1985 | url-access = registration }}</ref> – First widely distributed version, developed by McCarthy and others at MIT. So named because it contained several improvements on the original "LISP 1" interpreter, but was not a major restructuring as the planned [[LISP 2]] would be.
*[[Stanford LISP]] 1.6<ref>{{Cite book| url = http://www.softwarepreservation.org/projects/LISP/stanford/SAILON-28.6.pdf | format = PDF | title = Stanford LISP 1.6 Manual | first1 = Lynn H. | last1 = Quam | first2 = Whitfield | last2 = Diffle}}</ref> – This was a successor to LISP 1.5 developed at the [[Stanford AI Lab]], and widely distributed to [[PDP-10]] systems running the [[TOPS-10]] operating system. It was rendered obsolete by Maclisp and InterLisp.
*[[Maclisp|MACLISP]]<ref>{{cite web| url = http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt | title = Maclisp Reference Manual | date = March 3, 1979 | archiveurl = https://web.archive.org/web/20071214064433/http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt | archivedate = 2007-12-14}}</ref> – developed for MIT's [[Project MAC]], MACLISP is a direct descendant of LISP 1.5. It ran on the PDP-10 and [[Multics]] systems. MACLISP would later come to be called Maclisp, and is often referred to as MacLisp. The "MAC" in MACLISP is related neither to Apple's [[Macintosh]] nor to [[John McCarthy (computer scientist)|McCarthy]].
*[[Interlisp]]<ref>{{Cite book | url = http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf | format = PDF | title = InterLisp Reference Manual | first = Warren | last = Teitelman | year = 1974 | access-date = 2006-08-19 | archive-url = https://web.archive.org/web/20060602134835/http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf | archive-date = 2006-06-02 | url-status = dead }}</ref> – developed at [[BBN Technologies]] for PDP-10 systems running the [[TENEX (operating system)|TENEX operating system]], later adopted as a "West coast" Lisp for the Xerox Lisp machines as [[InterLisp-D]]. A small version called "InterLISP 65" was published for the [[MOS 6502|6502]]-based [[Atari 8-bit family]] computer line. For quite some time, Maclisp and InterLisp were strong competitors.
*[[Franz Lisp]] – originally a [[University of California, Berkeley]] project; later developed by Franz Inc. The name is a humorous deformation of the name "[[Franz Liszt]]", and does not refer to [[Allegro Common Lisp]], the dialect of Common Lisp sold by Franz Inc., in more recent years.
*[[XLISP]], which [[AutoLISP]] was based on.
*[[Standard Lisp]] and [[Portable Standard Lisp]] were widely used and ported, especially with the Computer Algebra System REDUCE.
*[[ZetaLisp]], also termed Lisp Machine Lisp – used on the [[Lisp machine]]s, direct descendant of Maclisp. ZetaLisp had a big influence on Common Lisp.
*[[LeLisp]] is a French Lisp dialect. One of the first [[Graphical user interface builder|Interface Builders]] (called SOS Interface<ref>[https://hal.archives-ouvertes.fr/file/index/docid/70041/filename/RT-0126.pdf Outils de generation d’interfaces : etat de l’art et classification by H. El Mrabet]</ref>) was written in LeLisp.
*[[Scheme (programming language)|Scheme]] (1975).<ref>ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>
*[[Common Lisp]] (1984), as described by ''[[Common Lisp the Language]]'' – a consolidation of several divergent attempts (ZetaLisp, [[Spice Lisp]], [[NIL (programming language)|NIL]], and [[S-1 Lisp]]) to create successor dialects<ref>{{Cite book| chapterurl = https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node6.html | title = Common Lisp the Language | edition = 2nd | chapter = Purpose | first = Guy L., Jr. | last = Steele| isbn = 0-13-152414-3}}</ref> to Maclisp, with substantive influences from the Scheme dialect as well. This version of Common Lisp was available for wide-ranging platforms and was accepted by many as a [[de facto standard]]<ref>{{cite web| url = https://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/faq-doc-13.html | title = History: Where did Lisp come from? | work = FAQ: Lisp Frequently Asked Questions 2/7 | date = 20 February 1996 | first1 = Mark | last1 = Kantrowitz | first2 = Barry | last2 = Margolin}}</ref> until the publication of ANSI Common Lisp (ANSI X3.226-1994). Among the most widespread sub-dialects of Common Lisp are [[Steel Bank Common Lisp]] (SBCL), CMU Common Lisp (CMU-CL), Clozure OpenMCL (not to be confused with Clojure!), GNU CLisp, and later versions of Franz Lisp; all of them adhere to the later ANSI CL standard (see below).
*[[Dylan (programming language)|Dylan]] was in its first version a mix of Scheme with the Common Lisp Object System.
*[[EuLisp]] – attempt to develop a new efficient and cleaned-up Lisp.
*[[ISLISP]] – attempt to develop a new efficient and cleaned-up Lisp. Standardized as ISO/IEC 13816:1997<ref>{{cite web|url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22987 |title=ISO/IEC 13816:1997 |publisher=Iso.org |date=2007-10-01 |accessdate=2013-11-15}}</ref> and later revised as ISO/IEC 13816:2007:<ref>{{cite web|url=http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44338 |title=ISO/IEC 13816:2007 |publisher=Iso.org |date=2013-10-30 |accessdate=2013-11-15}}</ref> ''Information technology – Programming languages, their environments and system software interfaces – Programming language ISLISP''.
*IEEE [[Scheme (programming language)|Scheme]] – IEEE standard, 1178–1990 (R1995)
*ANSI [[Common Lisp]] – an [[American National Standards Institute]] (ANSI) [[Standardization|standard]] for Common Lisp, created by subcommittee [[X3J13]], chartered<ref>{{cite web| url = http://www.nhplace.com/kent/CL/x3j13-86-020.html | title = X3J13 Charter}}</ref> to begin with ''Common Lisp: The Language'' as a base document and to work through a public [[Consensus decision-making|consensus]] process to find solutions to shared issues of [[Portability (software)|portability]] of programs and [[Computer compatibility|compatibility]] of Common Lisp implementations. Although formally an ANSI standard, the implementation, sale, use, and influence of ANSI Common Lisp has been and continues to be seen worldwide.
*[[ACL2]] or "A Computational Logic for Applicative Common Lisp", an applicative (side-effect free) variant of Common LISP. ACL2 is both a programming language which can model computer systems, and a tool to help proving properties of those models.
*[[Clojure]], a recent dialect of Lisp which compiles to the [[Java virtual machine]] and has a particular focus on [[Concurrency (computer science)|concurrency]].
*[[Game Oriented Assembly Lisp]] (or GOAL) is a video game programming language developed by Andy Gavin and the [[Jak and Daxter]] team at [[Naughty Dog]]. It was written using Allegro Common Lisp and used in the development of the entire [[Jak and Daxter|Jak and Daxter series of games]].
===2000 to present===
After having declined somewhat in the 1990s, Lisp has experienced a resurgence of interest after 2000. Most new activity has been focused around implementations of [[Common Lisp]], [[Scheme (programming language)|Scheme]], [[Emacs Lisp]], [[Clojure]], and [[Racket (programming language)|Racket]], and includes development of new portable libraries and applications.
Many new Lisp programmers were inspired by writers such as [[Paul Graham (computer programmer)|Paul Graham]] and [[Eric S. Raymond]] to pursue a language others considered antiquated. New Lisp programmers often describe the language as an eye-opening experience and claim to be substantially more productive than in other languages.<ref>{{cite web |title=The Road To Lisp Survey |url=http://wiki.alu.org/The_Road_To_Lisp_Survey |accessdate=2006-10-13 |archive-url=https://web.archive.org/web/20061004031130/http://wiki.alu.org/The_Road_To_Lisp_Survey |archive-date=2006-10-04 |url-status=dead }}</ref> This increase in awareness may be contrasted to the "[[AI winter]]" and Lisp's brief gain in the mid-1990s.<ref>{{cite web |url=http://www.faqs.org/docs/artu/ch14s05.html |title=Trends for the Future |publisher=Faqs.org |accessdate=2013-11-15}}</ref>
Dan Weinreb lists in his survey of Common Lisp implementations<ref>{{cite web|last=Weinreb|first=Daniel|title=Common Lisp Implementations: A Survey|url=http://common-lisp.net/~dlw/LispSurvey.html|accessdate=4 April 2012|archive-url=https://web.archive.org/web/20120421181340/http://common-lisp.net/~dlw/LispSurvey.html#|archive-date=2012-04-21|url-status=dead}}</ref> eleven actively maintained Common Lisp implementations. Scieneer Common Lisp is a new commercial implementation forked from CMUCL with a first release in 2002.
The [[open-source-software movement|open source]] community has created new supporting infrastructure: [[CLiki]] is a wiki that collects Common Lisp related information, the [[Common Lisp directory]] lists resources, #lisp is a popular IRC channel and allows the sharing and commenting of code snippets (with support by [[lisppaste]], an [[IRC bot]] written in Lisp), [[Planet Lisp]] collects the contents of various Lisp-related blogs, on [[LispForum]] users discuss Lisp topics, [[Lispjobs]] is a service for announcing job offers and there is a weekly news service, ''[[Weekly Lisp News]]''. ''Common-lisp.net'' is a hosting site for open source Common Lisp projects. [[Quicklisp]] is a library manager for Common Lisp.
Fifty years of Lisp (1958–2008) was celebrated at LISP50@OOPSLA.<ref>{{cite web|url=http://www.lisp50.org/ |title=LISP50@OOPSLA |publisher=Lisp50.org |accessdate=2013-11-15}}</ref> There are regular local user meetings in Boston, Vancouver, and Hamburg. Other events include the European Common Lisp Meeting, the European Lisp Symposium and an International Lisp Conference.
The Scheme community actively maintains [[Scheme (programming language)#Implementations|over twenty implementations]]. Several significant new implementations (Chicken, Gambit, Gauche, Ikarus, Larceny, Ypsilon) have been developed in the 2000s (decade). The Revised<sup>5</sup> Report on the Algorithmic Language Scheme<ref>[http://www.schemers.org/Documents/Standards/R5RS/ Documents: Standards: R5RS]. schemers.org (2012-01-11). Retrieved on 2013-07-17.</ref> standard of Scheme was widely accepted in the Scheme community. The [[Scheme Requests for Implementation]] process has created a lot of quasi standard libraries and extensions for Scheme. User communities of individual Scheme implementations continue to grow. A new language standardization process was started in 2003 and led to the R<sup>6</sup>RS Scheme standard in 2007. Academic use of Scheme for teaching computer science seems to have declined somewhat. Some universities are no longer using Scheme in their computer science introductory courses;<ref>{{cite news|url=http://cemerick.com/2009/03/24/why-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program/|title=Why MIT now uses python instead of scheme for its undergraduate CS program|date=March 24, 2009|work=cemerick.com|accessdate=November 10, 2013}}</ref><ref>{{cite news|url=http://mitadmissions.org/blogs/entry/the_end_of_an_era_1|title=The End of an Era|first=Evan|last=Broder|date=January 8, 2008|work=mitadmissions.org|accessdate=November 10, 2013}}</ref> MIT now uses [[Python (programming language)|Python]] instead of Scheme for its undergraduate [[computer science]] program and MITx massive open online course.<ref name="MITEECS-Python">{{cite web |title=MIT EECS Undergraduate Programs |url=https://www.eecs.mit.edu/academics-admissions/undergraduate-programs |website=www.eecs.mit.edu |publisher=MIT Electrical Engineering & Computer Science |accessdate=31 December 2018}}</ref><ref name="MITx-Phyton">{{cite web |title=MITx introductory Python course hits 1.2 million enrollments |url=https://www.eecs.mit.edu/news-events/announcements/mitx-introductory-python-course-hits-12-million-enrollments |website=MIT EECS |publisher=MIT Electrical Engineering & Computer Science |accessdate=31 December 2018}}</ref>
There are several new dialects of Lisp: [[Arc (programming language)|Arc]], [[Hy]], [[Nu (programming language)|Nu]], [[Liskell]], and [[LFE (programming language)|LFE]] (Lisp Flavored Erlang). The parser for [[Julia (programming language)|Julia]] is implemented in Femtolisp, a dialect of [[Scheme (programming language)|Scheme]] (Julia is inspired by Scheme, which in turn is a Lisp dialect).
In October 2019, Paul Graham released [http://paulgraham.com/bel.html a specification for Bel], "a new dialect of Lisp."
==Major dialects==
[[Common Lisp]] and [[Scheme (programming language)|Scheme]] represent two major streams of Lisp development. These languages embody significantly different design choices.
[[Common Lisp]] is a successor to [[Maclisp]]. The primary influences were [[Lisp Machine Lisp]], Maclisp, [[NIL (programming language)|NIL]], [[S-1 Lisp]], [[Spice Lisp]], and Scheme.<ref>Chapter 1.1.2, History, ANSI CL Standard</ref> It has many of the features of Lisp Machine Lisp (a large Lisp dialect used to program [[Lisp Machine]]s), but was designed to be efficiently implementable on any personal computer or workstation. Common Lisp is a general-purpose programming language and thus has a large language standard including many built-in data types, functions, macros and other language elements, and an object system ([[Common Lisp Object System]]). Common Lisp also borrowed certain features from Scheme such as [[lexical scoping]] and [[lexical closure]]s. Common Lisp implementations are available for targeting different platforms such as the [[LLVM]],<ref>[https://www.cliki.net/Clasp] Clasp is a Common Lisp implementation that interoperates with C++ and uses LLVM for [[just-in-time compilation]] (JIT) to native code.</ref> the [[Java virtual machine]],<ref>[https://common-lisp.net/project/armedbear/] "Armed Bear Common Lisp (ABCL) is a full implementation of the Common Lisp language featuring both an interpreter and a compiler, running in the JVM"</ref>
x86-64, PowerPC, Alpha, ARM, Motorola 68000, and MIPS,<ref>[https://common-lisp.net/~dlw/LispSurvey.html] {{Webarchive|url=https://web.archive.org/web/20180622083812/https://common-lisp.net/~dlw/LispSurvey.html# |date=2018-06-22 }} Common Lisp Implementations: A Survey</ref> and operating systems such as Windows, macOS, Linux, Solaris, FreeBSD, NetBSD, OpenBSD, Dragonfly BSD, and Heroku.<ref>[https://www.cliki.net/Common+Lisp+implementation] Comparison of actively developed Common Lisp implementations</ref>
Scheme is a statically scoped and properly tail-recursive dialect of the Lisp programming language invented by [[Guy L. Steele, Jr.]] and [[Gerald Jay Sussman]]. It was designed to have exceptionally clear and simple semantics and few different ways to form expressions. Designed about a decade earlier than Common Lisp, [[Scheme (programming language)|Scheme]] is a more minimalist design. It has a much smaller set of standard features but with certain implementation features (such as [[tail-call optimization]] and full [[continuation]]s) not specified in Common Lisp. A wide variety of programming paradigms, including imperative, functional, and message passing styles, find convenient expression in Scheme. Scheme continues to evolve with a series of standards (Revised<sup>n</sup> Report on the Algorithmic Language Scheme) and a series of [[Scheme Requests for Implementation]].
[[Clojure]] is a recent dialect of Lisp that targets mainly the [[Java virtual machine]], and the [[Common Language Runtime]] (CLR), the [[Python (programming language)|Python]] VM, the Ruby VM [[YARV]], and compiling to [[JavaScript]]. It is designed to be a pragmatic general-purpose language. Clojure draws considerable influences from [[Haskell (programming language)|Haskell]] and places a very strong emphasis on immutability.<ref name="clojure-immutability">[http://www.infoq.com/articles/in-depth-look-clojure-collections An In-Depth Look at Clojure Collections], Retrieved 2012-06-24</ref> Clojure provides access to Java frameworks and libraries, with optional type hints and [[type inference]], so that calls to Java can avoid reflection and enable fast primitive operations. Clojure is not designed to be backwards compatible with other Lisp dialects.<ref>{{cite web |title=Clojure rational |url=https://clojure.org/about/rationale |accessdate=27 August 2019 |quote=Clojure is a Lisp not constrained by backwards compatibility}}</ref>
Further, Lisp dialects are used as [[scripting language]]s in many applications, with the best-known being [[Emacs Lisp]] in the [[Emacs]] editor, [[AutoLISP]] and later [[Visual Lisp]] in [[AutoCAD]], Nyquist in [[Audacity (audio editor)|Audacity]], Scheme in [[LilyPond]]. The potential small size of a useful Scheme interpreter makes it particularly popular for embedded scripting. Examples include [[SIOD]] and [[TinyScheme]], both of which have been successfully embedded in the [[GIMP]] image processor under the generic name "Script-fu".<ref name="script-fu">[http://www.gimp.org/docs/script-fu-update.html Script-fu In GIMP 2.4], Retrieved 2009-10-29</ref> LIBREP, a Lisp interpreter by John Harper originally based on the [[Emacs Lisp]] language, has been embedded in the [[Sawfish (window manager)|Sawfish]] [[window manager]].<ref name="librep">[http://sawfish.wikia.com/wiki/Librep librep] at Sawfish Wikia, retrieved 2009-10-29</ref>
===Standardized dialects===
Lisp has officially standardized dialects: [[Scheme (programming language)#R6RS|R6RS Scheme]], [[Scheme (programming language)#R7RS|R7RS Scheme]], IEEE Scheme,<ref>{{cite web |url=https://standards.ieee.org/standard/1178-1990.html |website=IEEE 1178-1990 - IEEE Standard for the Scheme Programming Language |accessdate=27 August 2019 |title=IEEE Scheme}}</ref> [[ANSI Common Lisp]] and ISO [[ISLISP]].
==Language innovations==
Lisp was the first language where the structure of program code is represented faithfully and directly in a standard data structure—a quality much later dubbed "[[homoiconicity]]". Thus, Lisp functions can be manipulated, altered or even created within a Lisp program without lower-level manipulations. This is generally considered one of the main advantages of the language with regard to its expressive power, and makes the language suitable for syntactic macros and [[metacircular evaluation]].
A conditional using an ''[[if–then–else]]'' syntax was invented by McCarthy in a Fortran context. He proposed its inclusion in [[ALGOL]], but it was not made part of the [[Algol 58]] specification. For Lisp, McCarthy used the more general ''cond''-structure.<ref>{{cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node2.html|title=LISP prehistory - Summer 1956 through Summer 1958.|quote=I invented conditional expressions in connection with a set of chess legal move routines I wrote in FORTRAN for the IBM 704 at M.I.T. during 1957–58 ... A paper defining conditional expressions and proposing their use in Algol was sent to the Communications of the ACM but was arbitrarily demoted to a letter to the editor, because it was very short.}}</ref> [[Algol 60]] took up ''if–then–else'' and popularized it.
Lisp deeply influenced [[Alan Kay]], the leader of the research team that developed [[Smalltalk]] at [[Xerox PARC]]; and in turn Lisp was influenced by Smalltalk, with later dialects adopting object-oriented programming features (inheritance classes, encapsulating instances, message passing, etc.) in the 1970s. The [[Flavors (programming language)|Flavors]] object system introduced the concept of [[multiple inheritance]] and the [[mixin]]. The [[Common Lisp Object System]] provides multiple inheritance, multimethods with [[multiple dispatch]], and first-class [[generic functions]], yielding a flexible and powerful form of [[dynamic dispatch]]. It has served as the template for many subsequent Lisp (including [[Scheme (programming language)|Scheme]]) object systems, which are often implemented via a [[Metaobject#Metaobject Protocol|metaobject protocol]], a [[Reflection (computer science)|reflective]] [[Metacircular evaluator|metacircular design]] in which the object system is defined in terms of itself: Lisp was only the second language after Smalltalk (and is still one of the very few languages) to possess such a metaobject system. Many years later, Alan Kay suggested that as a result of the confluence of these features, only Smalltalk and Lisp could be regarded as properly conceived object-oriented programming systems.<ref>{{cite web|date=2003-07-23|url=http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en|title=Meaning of 'Object-Oriented Programming' According to Dr. Alan Kay|quote=I didn't understand the monster LISP idea of tangible metalanguage then, but got kind of close with ideas about extensible languages ... The second phase of this was to finally understand LISP and then using this understanding to make much nicer and smaller and more powerful and more late bound understructures ... OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them.}}</ref>
Lisp introduced the concept of [[Garbage collection (computer science)|automatic garbage collection]], in which the system walks the [[Heap (memory management)|heap]] looking for unused memory. Progress in modern sophisticated garbage collection algorithms such as generational garbage collection was stimulated by its use in Lisp.<ref>{{citation |last=Lieberman |first=Henry |last2=Hewitt |first2=Carl |title=A Real-Time Garbage Collector Based on the Lifetimes of Objects |url=http://web.media.mit.edu/~lieber/Lieberary/GC/Realtime/Realtime.html |journal=Communications of the ACM |volume=26 |issue=6 |date=June 1983 |pages=419–429 |doi=10.1145/358141.358147|citeseerx=10.1.1.4.8633 }}</ref>
[[Edsger W. Dijkstra]] in his 1972 [[Turing Award]] lecture said,
:"With a few very basic principles at its foundation, it [LISP] has shown a remarkable stability. Besides that, LISP has been the carrier for a considerable number of in a sense our most sophisticated computer applications. LISP has jokingly been described as “the most intelligent way to misuse a computer”. I think that description a great compliment because it transmits the full flavour of liberation: it has assisted a number of our most gifted fellow humans in thinking previously impossible thoughts."<ref>{{citation|url=http://www.cs.utexas.edu/~EWD/transcriptions/EWD03xx/EWD340.html|author=Edsger W. Dijkstra|year=1972|title=The Humble Programmer (EWD 340)}} (ACM Turing Award lecture).</ref>
Largely because of its resource requirements with respect to early computing hardware (including early microprocessors), Lisp did not become as popular outside of the [[AI]] community as [[Fortran]] and the [[ALGOL]]-descended [[C (programming language)|C]] language. Because of its suitability to complex and dynamic applications, Lisp is enjoying some resurgence of popular interest in the 2010s.<ref>{{cite web|url=https://www.linkedin.com/pulse/look-clojure-lisp-resurgence-todd-towles|title=A Look at Clojure and the Lisp Resurgence}}</ref>
==Syntax and semantics==
:'''''Note''': This article's examples are written in [[Common Lisp]] (though most are also valid in [[Scheme (programming language)|Scheme]]).''
===Symbolic expressions (S-expressions)===
Lisp is an [[expression oriented language]]. Unlike most other languages, no distinction is made between "expressions" and [[Statement (programming)|"statements"]];{{dubious|date=April 2013}}<!-- (progn ...), (setq ...). There is no syntactic distinction, but sequential evaluation is there. --> all code and data are written as expressions. When an expression is ''evaluated'', it produces a value (in Common Lisp, possibly multiple values), which can then be embedded into other expressions. Each value can be any data type.
McCarthy's 1958 paper introduced two types of syntax: ''Symbolic expressions'' ([[S-expression]]s, sexps), which mirror the internal representation of code and data; and ''Meta expressions'' ([[M-expression]]s), which express functions of S-expressions. M-expressions never found favor, and almost all Lisps today use S-expressions to manipulate both code and data.
The use of parentheses is Lisp's most immediately obvious difference from other programming language families. As a result, students have long given Lisp nicknames such as ''Lost In Stupid Parentheses'', or ''Lots of Irritating Superfluous Parentheses''.<ref name="LEVIN2">{{cite web| title=The Jargon File - Lisp| url=http://www.catb.org/~esr/jargon/html/L/LISP.html| accessdate=2006-10-13}}</ref><!-- Add NO more nicknames. People can check the Jargon File for them. --> However, the S-expression syntax is also responsible for much of Lisp's power: the syntax is extremely regular, which facilitates manipulation by computer. However, the syntax of Lisp is not limited to traditional parentheses notation. It can be extended to include alternative notations. For example, XMLisp is a Common Lisp extension that employs the [[Metaobject#Metaobject protocol|metaobject protocol]] to integrate S-expressions with the Extensible Markup Language ([[XML]]).
The reliance on expressions gives the language great flexibility. Because Lisp [[function (programming)|functions]] are written as lists, they can be processed exactly like data. This allows easy writing of programs which manipulate other programs ([[metaprogramming]]). Many Lisp dialects exploit this feature using macro systems, which enables extension of the language almost without limit.
===Lists===
A Lisp list is written with its elements separated by [[Whitespace character|whitespace]], and surrounded by parentheses. For example, {{Lisp2|(1 2 foo)}} is a list whose elements are the three ''atoms'' {{Lisp2|1}}, {{Lisp2|2}}, and [[foo|{{Lisp2|foo}}]]. These values are implicitly typed: they are respectively two integers and a Lisp-specific data type called a "symbol", and do not have to be declared as such.
The empty list {{Lisp2|()}} is also represented as the special atom {{Lisp2|nil}}. This is the only entity in Lisp which is both an atom and a list.
Expressions are written as lists, using [[Polish notation|prefix notation]]. The first element in the list is the name of a function, the name of a macro, a lambda expression or the name of a "special operator" (see below). The remainder of the list are the arguments. For example, the function {{Lisp2|list}} returns its arguments as a list, so the expression
<syntaxhighlight lang="Lisp">
(list 1 2 (quote foo))
</syntaxhighlight>
evaluates to the list {{Lisp2|(1 2 foo)}}. The "quote" before the [[foo|{{Lisp2|foo}}]] in the preceding example is a "special operator" which returns its argument without evaluating it. Any unquoted expressions are recursively evaluated before the enclosing expression is evaluated. For example,
<syntaxhighlight lang="Lisp">
(list 1 2 (list 3 4))
</syntaxhighlight>
evaluates to the list {{Lisp2|(1 2 (3 4))}}. Note that the third argument is a list; lists can be nested.
===Operators===
Arithmetic operators are treated similarly. The expression
<syntaxhighlight lang="Lisp">
(+ 1 2 3 4)
</syntaxhighlight>
evaluates to 10. The equivalent under [[infix notation]] would be "{{Lisp2|1 + 2 + 3 + 4}}".
Lisp has no notion of operators as implemented in Algol-derived languages. Arithmetic operators in Lisp are [[variadic function]]s (or ''n-ary''), able to take any number of arguments. A C-style '++' increment operator is sometimes implemented under the name <tt>incf</tt> giving syntax
<syntaxhighlight lang="Lisp">
(incf x)
</syntaxhighlight>
equivalent to <tt>(setq x (+ x 1))</tt>, returning the new value of <tt>x</tt>.
"Special operators" (sometimes called "special forms") provide Lisp's control structure. For example, the special operator {{Lisp2|if}} takes three arguments. If the first argument is non-nil, it evaluates to the second argument; otherwise, it evaluates to the third argument. Thus, the expression
<syntaxhighlight lang="Lisp">
(if nil
(list 1 2 "foo")
(list 3 4 "bar"))
</syntaxhighlight>
evaluates to {{Lisp2|(3 4 "bar")}}. Of course, this would be more useful if a non-trivial expression had been substituted in place of {{Lisp2|nil}}.
Lisp also provides logical operators '''and''', '''or''' and '''not'''. The '''and''' and '''or''' operators do [[short circuit evaluation]] and will return their first nil and non-nil argument respectively.
<syntaxhighlight lang="Lisp">
(or (and "zero" nil "never") "James" 'task 'time)
</syntaxhighlight>
will evaluate to "James".
===Lambda expressions and function definition===
Another special operator, {{Lisp2|lambda}}, is used to bind variables to values which are then evaluated within an expression. This operator is also used to create functions: the arguments to {{Lisp2|lambda}} are a list of arguments, and the expression or expressions to which the function evaluates (the returned value is the value of the last expression that is evaluated). The expression
<syntaxhighlight lang="Lisp">
(lambda (arg) (+ arg 1))
</syntaxhighlight>
evaluates to a function that, when applied, takes one argument, binds it to {{Lisp2|arg}} and returns the number one greater than that argument. Lambda expressions are treated no differently from named functions; they are invoked the same way. Therefore, the expression
<syntaxhighlight lang="Lisp">
((lambda (arg) (+ arg 1)) 5)
</syntaxhighlight>
evaluates to {{Lisp2|6}}. Here, we're doing a function application: we execute the [[anonymous function]] by passing to it the value 5.
Named functions are created by storing a lambda expression in a symbol using the [[defun]] macro.
<syntaxhighlight lang="Lisp">
(defun foo (a b c d) (+ a b c d))
</syntaxhighlight>
{{Lisp2|(defun f (a) b...)}} defines a new function named {{Lisp2|f}} in the global environment. It is conceptually similar to the expression:
<syntaxhighlight lang="Lisp">
(setf (fdefinition 'f) #'(lambda (a) (block f b...)))
</syntaxhighlight>
===Atoms===
In the original '''LISP''' there were two fundamental [[data type]]s: atoms and lists. A list was a finite ordered sequence of elements, where each element is either an atom or a list, and an atom was a [[number]] or a symbol. A symbol was essentially a unique named item, written as an [[alphanumeric]] string in [[source code]], and used either as a variable name or as a data item in [[symbolic processing]]. For example, the list {{Lisp2|(FOO (BAR 1) 2)}} contains three elements: the symbol {{Lisp2|FOO}}, the list {{Lisp2|(BAR 1)}}, and the number 2.
The essential difference between atoms and lists was that atoms were immutable and unique. Two atoms that appeared in different places in source code but were written in exactly the same way represented the same object,{{Citation needed|date=November 2008}} whereas each list was a separate object that could be altered independently of other lists and could be distinguished from other lists by comparison operators.
As more data types were introduced in later Lisp dialects, and [[programming style]]s evolved, the concept of an atom lost importance.{{Citation needed|date=November 2008}} Many dialects still retained the predicate ''atom'' for [[legacy compatibility]],{{Citation needed|date=November 2008}} defining it true for any object which is not a cons.
===Conses and lists===
{{Main|Cons}}
[[File:Cons-cells.svg|thumb|right|300px|Box-and-[[pointer (computer programming)|pointer]] diagram for the list (42 69 613)]]
A Lisp list is implemented as a [[singly linked list]].<ref name=SebestaLanguages>{{cite book |last1=Sebesta |first1=Robert W. |title=Concepts of Programming Languages |chapter="2.4 Functional Programming: LISP";"6.9 List Types";"15.4 The First Functional Programming Language: LISP" |date=2012 |publisher=Addison-Wesley |location=Boston, MA, USA |isbn=978-0-13-139531-2 |pages=47–52;281–284;677–680 |edition=10th |url=https://www.pearson.com/us/higher-education/product/Sebesta-Concepts-of-Programming-Languages-10th-Edition/9780131395312.html |language=en |format=print}}</ref> Each cell of this list is called a ''cons'' (in Scheme, a ''pair''), and is composed of two [[pointer (computer programming)|pointer]]s, called the ''car'' and ''cdr''. These are respectively equivalent to the {{Lisp2|data}} and {{Lisp2|next}} fields discussed in the article ''[[linked list]]''.
Of the many data structures that can be built out of cons cells, one of the most basic is called a ''proper list''. A proper list is either the special {{Lisp2|nil}} (empty list) symbol, or a cons in which the {{Lisp2|car}} points to a datum (which may be another cons structure, such as a list), and the {{Lisp2|cdr}} points to another proper list.
If a given cons is taken to be the head of a linked list, then its car points to the first element of the list, and its cdr points to the rest of the list. For this reason, the {{Lisp2|car}} and {{Lisp2|cdr}} functions are also called {{Lisp2|first}} and {{Lisp2|rest}} when referring to conses which are part of a linked list (rather than, say, a tree).
Thus, a Lisp list is not an atomic object, as an instance of a container class in C++ or Java would be. A list is nothing more than an aggregate of linked conses. A variable which refers to a given list is simply a pointer to the first cons in the list. Traversal of a list can be done by ''cdring down'' the list; that is, taking successive cdrs to visit each cons of the list; or by using any of several [[higher-order function]]s to map a function over a list.
Because conses and lists are so universal in Lisp systems, it is a common misconception that they are Lisp's only data structures. In fact, all but the most simplistic Lisps have other data structures, such as vectors ([[Array data type|arrays]]), hash tables, structures, and so forth.
====S-expressions represent lists====
Parenthesized S-expressions represent linked list structures. There are several ways to represent the same list as an S-expression. A cons can be written in ''dotted-pair notation'' as {{Lisp2|(a . b)}}, where {{Lisp2|a}} is the car and {{Lisp2|b}} the cdr. A longer proper list might be written {{Lisp2|(a . (b . (c . (d . nil))))}} in dotted-pair notation. This is conventionally abbreviated as {{Lisp2|(a b c d)}} in ''list notation''. An improper list<ref>NB: a so-called "dotted list" is only one kind of "improper list". The other kind is the "circular list" where the cons cells form a loop. Typically this is represented using #n=(...) to represent the target cons cell that will have multiple references, and #n# is used to refer to this cons. For instance, (#1=(a b) . #1#) would normally be printed as ((a b) a b) (without circular structure printing enabled), but makes the reuse of the cons cell clear. #1=(a . #1#) cannot normally be printed as it is circular, although (a...) is sometimes displayed, the CDR of the cons cell defined by #1= is itself.</ref> may be written in a combination of the two – as {{Lisp2|(a b c . d)}} for the list of three conses whose last cdr is {{Lisp2|d}} (i.e., the list {{Lisp2|(a . (b . (c . d)))}} in fully specified form).
====List-processing procedures====
Lisp provides many built-in procedures for accessing and controlling lists. Lists can be created directly with the {{Lisp2|list}} procedure, which takes any number of arguments, and returns the list of these arguments.
<syntaxhighlight lang="Lisp">
(list 1 2 'a 3)
;Output: (1 2 a 3)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(list 1 '(2 3) 4)
;Output: (1 (2 3) 4)
</syntaxhighlight>
Because of the way that lists are constructed from [[cons pair]]s, the {{Lisp2|cons}} procedure can be used to add an element to the front of a list. Note that the {{Lisp2|cons}} procedure is asymmetric in how it handles list arguments, because of how lists are constructed.
<syntaxhighlight lang="Lisp">
(cons 1 '(2 3))
;Output: (1 2 3)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(cons '(1 2) '(3 4))
;Output: ((1 2) 3 4)
</syntaxhighlight>
The {{Lisp2|append}} procedure appends two (or more) lists to one another. Because Lisp lists are linked lists, appending two lists has [[Big O notation|asymptotic time complexity]] <math>O(n)</math>
<syntaxhighlight lang="Lisp">
(append '(1 2) '(3 4))
;Output: (1 2 3 4)
</syntaxhighlight>
<syntaxhighlight lang="Lisp">
(append '(1 2 3) '() '(a) '(5 6))
;Output: (1 2 3 a 5 6)
</syntaxhighlight>
====Shared structure====
Lisp lists, being simple linked lists, can share structure with one another. That is to say, two lists can have the same ''tail'', or final sequence of conses. For instance, after the execution of the following Common Lisp code:
<syntaxhighlight lang="Lisp">
(setf foo (list 'a 'b 'c))
(setf bar (cons 'x (cdr foo)))
</syntaxhighlight>
the lists {{Lisp2|foo}} and {{Lisp2|bar}} are {{Lisp2|(a b c)}} and {{Lisp2|(x b c)}} respectively. However, the tail {{Lisp2|(b c)}} is the same structure in both lists. It is not a copy; the cons cells pointing to {{Lisp2|b}} and {{Lisp2|c}} are in the same memory locations for both lists.
Sharing structure rather than copying can give a dramatic performance improvement. However, this technique can interact in undesired ways with functions that alter lists passed to them as arguments. Altering one list, such as by replacing the {{Lisp2|c}} with a {{Lisp2|goose}}, will affect the other:
<syntaxhighlight lang="Lisp">
(setf (third foo) 'goose)
</syntaxhighlight>
This changes {{Lisp2|foo}} to {{Lisp2|(a b goose)}}, but thereby also changes {{Lisp2|bar}} to {{Lisp2|(x b goose)}} – a possibly unexpected result. This can be a source of bugs, and functions which alter their arguments are documented as ''destructive'' for this very reason.
Aficionados of [[functional programming]] avoid destructive functions. In the Scheme dialect, which favors the functional style, the names of destructive functions are marked with a cautionary exclamation point, or "bang"—such as {{Lisp2|set-car!}} (read ''set car bang''), which replaces the car of a cons. In the Common Lisp dialect, destructive functions are commonplace; the equivalent of {{Lisp2|set-car!}} is named {{Lisp2|rplaca}} for "replace car." This function is rarely seen however as Common Lisp includes a special facility, {{Lisp2|setf}}, to make it easier to define and use destructive functions. A frequent style in Common Lisp is to write code functionally (without destructive calls) when prototyping, then to add destructive calls as an optimization where it is safe to do so.
===Self-evaluating forms and quoting===
Lisp evaluates expressions which are entered by the user. Symbols and lists evaluate to some other (usually, simpler) expression – for instance, a symbol evaluates to the value of the variable it names; {{Lisp2|(+ 2 3)}} evaluates to {{Lisp2|5}}. However, most other forms evaluate to themselves: if entering {{Lisp2|5}} into Lisp, it returns {{Lisp2|5}}.
Any expression can also be marked to prevent it from being evaluated (as is necessary for symbols and lists). This is the role of the {{Lisp2|quote}} special operator, or its abbreviation {{Lisp2|'}} (one quotation mark). For instance, usually if entering the symbol {{Lisp2|foo}}, it returns the value of the corresponding variable (or an error, if there is no such variable). To refer to the literal symbol, enter {{Lisp2|(quote foo)}} or, usually, {{Lisp2|'foo}}.
{{anchor|Backquote}}Both Common Lisp and Scheme also support the ''backquote'' operator (termed ''[[quasiquote]]'' in Scheme), entered with the {{Lisp2|`}} character ([[Grave accent#Use in programming|grave accent]]). This is almost the same as the plain quote, except it allows expressions to be evaluated and their values interpolated into a quoted list with the comma {{Lisp2|,}} ''unquote'' and comma-at {{Lisp2|,@}} ''splice'' operators. If the variable {{Lisp2|snue}} has the value {{Lisp2|(bar baz)}} then {{Lisp2|`(foo ,snue)}} evaluates to {{Lisp2|(foo (bar baz))}}, while {{Lisp2|`(foo ,@snue)}} evaluates to {{Lisp2|(foo bar baz)}}. The backquote is most often used in defining macro expansions.<ref>{{cite web|url=http://www.cs.washington.edu/education/courses/cse341/04wi/lectures/14-scheme-quote.html |title=CSE 341: Scheme: Quote, Quasiquote, and Metaprogramming |publisher=Cs.washington.edu |date=1999-02-22 |accessdate=2013-11-15}}</ref><ref>[http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf Quasiquotation in Lisp] {{Webarchive|url=https://web.archive.org/web/20130603114956/http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf |date=2013-06-03 }}, Alan Bawden</ref>
Self-evaluating forms and quoted forms are Lisp's equivalent of literals. It may be possible to modify the values of (mutable) literals in program code. For instance, if a function returns a quoted form, and the code that calls the function modifies the form, this may alter the behavior of the function on subsequent invocations.
<syntaxhighlight lang="lisp">
(defun should-be-constant ()
'(one two three))
(let ((stuff (should-be-constant)))
(setf (third stuff) 'bizarre)) ; bad!
(should-be-constant) ; returns (one two bizarre)
</syntaxhighlight>
Modifying a quoted form like this is generally considered bad style, and is defined by ANSI Common Lisp as erroneous (resulting in "undefined" behavior in compiled files, because the file-compiler can coalesce similar constants, put them in write-protected memory, etc.).
Lisp's formalization of quotation has been noted by [[Douglas Hofstadter]] (in ''[[Gödel, Escher, Bach]]'') and others as an example of the [[philosophy|philosophical]] idea of [[self-reference]].
===Scope and closure===
The Lisp family splits over the use of [[dynamic scoping|dynamic]] or [[static scoping|static]] (a.k.a. lexical) [[scope (programming)|scope]]. Clojure, Common Lisp and Scheme make use of static scoping by default, while [[newLISP]], [[Picolisp]] and the embedded languages in [[Emacs]] and [[AutoCAD]] use dynamic scoping. Since version 24.1, Emacs uses both dynamic and lexical scoping.
===List structure of program code; exploitation by macros and compilers===
A fundamental distinction between Lisp and other languages is that in Lisp, the textual representation of a program is simply a human-readable description of the same internal data structures (linked lists, symbols, number, characters, etc.) as would be used by the underlying Lisp system.
Lisp uses this to implement a very powerful macro system. Like other macro languages such as [[C (programming language)|C]], a macro returns code that can then be compiled. However, unlike C macros, the macros are Lisp functions and so can exploit the full power of Lisp.
Further, because Lisp code has the same structure as lists, macros can be built with any of the list-processing functions in the language. In short, anything that Lisp can do to a data structure, Lisp macros can do to code. In contrast, in most other languages, the parser's output is purely internal to the language implementation and cannot be manipulated by the programmer.
This feature makes it easy to develop ''efficient'' languages within languages. For example, the Common Lisp Object System can be implemented cleanly as a language extension using macros. This means that if an application needs a different inheritance mechanism, it can use a different object system. This is in stark contrast to most other languages; for example, Java does not support multiple inheritance and there is no reasonable way to add it.
In simplistic Lisp implementations, this list structure is directly [[interpreter (computing)|interpreted]] to run the program; a function is literally a piece of list structure which is traversed by the interpreter in executing it. However, most substantial Lisp systems also include a compiler. The compiler translates list structure into machine code or [[bytecode]] for execution. This code can run as fast as code compiled in conventional languages such as C.
Macros expand before the compilation step, and thus offer some interesting options. If a program needs a precomputed table, then a macro might create the table at compile time, so the compiler need only output the table and need not call code to create the table at run time. Some Lisp implementations even have a mechanism, <code>eval-when</code>, that allows code to be present during compile time (when a macro would need it), but not present in the emitted module.<ref>[https://www.gnu.org/software/emacs/manual/html_node/cl/Time-of-Evaluation.html Time of Evaluation - Common Lisp Extensions]. Gnu.org. Retrieved on 2013-07-17.</ref>
===Evaluation and the read–eval–print loop===
Lisp languages are often used with an interactive [[command line]], which may be combined with an [[integrated development environment]] (IDE). The user types in expressions at the command line, or directs the IDE to transmit them to the Lisp system. Lisp ''reads'' the entered expressions, ''evaluates'' them, and ''prints'' the result. For this reason, the Lisp command line is called a ''[[read–eval–print loop]]'' ([[REPL]]).
The basic operation of the REPL is as follows. This is a simplistic description which omits many elements of a real Lisp, such as quoting and macros.
The {{Lisp2|read}} function accepts textual S-expressions as input, and parses them into an internal data structure. For instance, if you type the text {{Lisp2|(+ 1 2)}} at the prompt, {{Lisp2|read}} translates this into a linked list with three elements: the symbol {{Lisp2|+}}, the number 1, and the number 2. It so happens that this list is also a valid piece of Lisp code; that is, it can be evaluated. This is because the car of the list names a function—the addition operation.
Note that a {{Lisp2|foo}} will be read as a single symbol. {{Lisp2|123}} will be read as the number one hundred and twenty-three. {{Lisp2|"123"}} will be read as the string "123".
The {{Lisp2|eval}} function evaluates the data, returning zero or more other Lisp data as a result. Evaluation does not have to mean interpretation; some Lisp systems compile every expression to native machine code. It is simple, however, to describe evaluation as interpretation: To evaluate a list whose car names a function, {{Lisp2|eval}} first evaluates each of the arguments given in its cdr, then applies the function to the arguments. In this case, the function is addition, and applying it to the argument list {{Lisp2|(1 2)}} yields the answer {{Lisp2|3}}. This is the result of the evaluation.
The symbol {{Lisp2|foo}} evaluates to the value of the symbol foo. Data like the string "123" evaluates to the same string. The list {{Lisp2|(quote (1 2 3))}} evaluates to the list (1 2 3).
It is the job of the {{Lisp2|print}} function to represent output to the user. For a simple result such as {{Lisp2|3}} this is trivial. An expression which evaluated to a piece of list structure would require that {{Lisp2|print}} traverse the list and print it out as an S-expression.
To implement a Lisp REPL, it is necessary only to implement these three functions and an infinite-loop function. (Naturally, the implementation of {{Lisp2|eval}} will be complex, since it must also implement all special operators like {{Lisp2|if}} or {{Lisp2|lambda}}.) This done, a basic REPL is one line of code: {{Lisp2|(loop (print (eval (read))))}}.
The Lisp REPL typically also provides input editing, an input history, error handling and an interface to the debugger.
Lisp is usually evaluated [[eager evaluation|eagerly]]. In [[Common Lisp]], arguments are evaluated in [[applicative order]] ('leftmost innermost'), while in [[Scheme programming language|Scheme]] order of arguments is undefined, leaving room for optimization by a compiler.
===Control structures===
Lisp originally had very few control structures, but many more were added during the language's evolution. (Lisp's original conditional operator, {{Lisp2|cond}}, is the precursor to later {{Lisp2|if-then-else}} structures.)
Programmers in the Scheme dialect often express loops using [[tail recursion]]. Scheme's commonality in academic computer science has led some students to believe that tail recursion is the only, or the most common, way to write iterations in Lisp, but this is incorrect. All oft-seen Lisp dialects have imperative-style iteration constructs, from Scheme's {{Lisp2|do}} loop to [[Common Lisp]]'s complex {{Lisp2|loop}} expressions. Moreover, the key issue that makes this an objective rather than subjective matter is that Scheme makes specific requirements for the handling of [[tail call]]s, and thus the reason that the use of tail recursion is generally encouraged for Scheme is that the practice is expressly supported by the language definition. By contrast, ANSI Common Lisp does not require<ref>[http://www.lispworks.com/documentation/HyperSpec/Body/03_bbc.htm 3.2.2.3 Semantic Constraints] in [http://www.lispworks.com/documentation/HyperSpec/Front/index.htm ''Common Lisp HyperSpec'']</ref> the optimization commonly termed a tail call elimination. Thus, the fact that tail recursive style as a casual replacement for the use of more traditional [[iteration]] constructs (such as {{Lisp2|do}}, {{Lisp2|dolist}} or {{Lisp2|loop}}) is discouraged<ref>4.3. Control Abstraction (Recursion vs. Iteration) in [http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf Tutorial on Good Lisp Programming Style] by [[Kent Pitman]] and [[Peter Norvig]], August, 1993.</ref> in Common Lisp is not just a matter of stylistic preference, but potentially one of efficiency (since an apparent tail call in Common Lisp may not compile as a simple [[Branch (computer science)|jump]]) and program correctness (since tail recursion may increase stack use in Common Lisp, risking [[stack overflow]]).
Some Lisp control structures are ''special operators'', equivalent to other languages' syntactic keywords. Expressions using these operators have the same surface appearance as function calls, but differ in that the arguments are not necessarily evaluated—or, in the case of an iteration expression, may be evaluated more than once.
In contrast to most other major programming languages, Lisp allows implementing control structures using the language. Several control structures are implemented as Lisp macros, and can even be macro-expanded by the programmer who wants to know how they work.
Both Common Lisp and Scheme have operators for non-local control flow. The differences in these operators are some of the deepest differences between the two dialects. Scheme supports ''re-entrant [[continuation]]s'' using the {{Lisp2|call/cc}} procedure, which allows a program to save (and later restore) a particular place in execution. Common Lisp does not support re-entrant continuations, but does support several ways of handling escape continuations.
Often, the same algorithm can be expressed in Lisp in either an imperative or a functional style. As noted above, Scheme tends to favor the functional style, using tail recursion and continuations to express control flow. However, imperative style is still quite possible. The style preferred by many Common Lisp programmers may seem more familiar to programmers used to structured languages such as C, while that preferred by Schemers more closely resembles pure-functional languages such as [[Haskell (programming language)|Haskell]].
Because of Lisp's early heritage in list processing, it has a wide array of higher-order functions relating to iteration over sequences. In many cases where an explicit loop would be needed in other languages (like a {{Lisp2|for}} loop in C) in Lisp the same task can be accomplished with a higher-order function. (The same is true of many functional programming languages.)
A good example is a function which in Scheme is called {{Lisp2|map}} and in Common Lisp is called {{Lisp2|mapcar}}. Given a function and one or more lists, {{Lisp2|mapcar}} applies the function successively to the lists' elements in order, collecting the results in a new list:
<syntaxhighlight lang="Lisp">
(mapcar #'+ '(1 2 3 4 5) '(10 20 30 40 50))
</syntaxhighlight>
This applies the {{Lisp2|+}} function to each corresponding pair of list elements, yielding the result {{Lisp2|(11 22 33 44 55)}}.
==Examples==
Here are examples of Common Lisp code.
The basic "[[Hello world]]" program:
<syntaxhighlight lang="Lisp">
(print "Hello world")
</syntaxhighlight>
Lisp syntax lends itself naturally to recursion. Mathematical problems such as the enumeration of recursively defined sets are simple to express in this notation.
Evaluate a number's [[factorial]]:
<syntaxhighlight lang="Lisp">
(defun factorial (n)
(if (= n 0) 1
(* n (factorial (- n 1)))))
</syntaxhighlight>
An alternative implementation takes less stack space than the previous version if the underlying Lisp system optimizes [[tail recursion]]:
<syntaxhighlight lang="Lisp">
(defun factorial (n &optional (acc 1))
(if (= n 0) acc
(factorial (- n 1) (* acc n))))
</syntaxhighlight>
Contrast with an iterative version which uses [[Common Lisp]]'s {{Lisp2|loop}} macro:
<syntaxhighlight lang="Lisp">
(defun factorial (n)
(loop for i from 1 to n
for fac = 1 then (* fac i)
finally (return fac)))
</syntaxhighlight>
The following function reverses a list. (Lisp's built-in ''reverse'' function does the same thing.)
<syntaxhighlight lang="Lisp">
(defun -reverse (list)
(let ((return-value '()))
(dolist (e list) (push e return-value))
return-value))
</syntaxhighlight>
==Object systems==
Various object systems and models have been built on top of, alongside, or into Lisp, including:
*The [[Common Lisp Object System]], CLOS, is an integral part of ANSI Common Lisp. CLOS descended from New Flavors and CommonLOOPS. ANSI Common Lisp was the first standardized object-oriented programming language (1994, ANSI X3J13).
*ObjectLisp<ref>pg 17 of Bobrow 1986</ref> or [[Object Lisp]], used by [[Lisp Machines Incorporated]] and early versions of Macintosh Common Lisp
*LOOPS (Lisp Object-Oriented Programming System) and the later [[CommonLOOPS]]
*[[Flavors (computer science)|Flavors]], built at [[Massachusetts Institute of Technology|MIT]], and its descendant New Flavors (developed by [[Symbolics]]).
*KR (short for Knowledge Representation), a [[Constraint satisfaction|constraint]]s-based object system developed to aid the writing of Garnet, a GUI library for [[Common Lisp]].
*[[Knowledge Engineering Environment]] (KEE) used an object system called UNITS and integrated it with an [[inference engine]]<ref>Veitch, p 108, 1988</ref> and a [[Truth maintenance systems|truth maintenance system]] (ATMS).
==See also==
* [[Self-modifying code]]
==References==
{{Reflist|30em}}
==Further reading==
{{Refbegin}}
*{{cite web
| last = McCarthy
| first = John
| authorlink =
| title = The implementation of Lisp
| work = History of Lisp
| publisher = Stanford University
| date = 1979-02-12
| url = http://www-formal.stanford.edu/jmc/history/lisp/node3.html
| doi =
| accessdate = 2008-10-17}}
*{{Cite conference
| first = Guy L.
| last = Steele, Jr.
| authorlink =
|author2=Richard P. Gabriel
| title = The evolution of Lisp
| conference = The second ACM SIGPLAN conference on History of programming languages
| pages = 231–270
| publisher = ACM
| year = 1993
| location = New York, NY
| url = http://www.dreamsongs.com/NewFiles/HOPL2-Uncut.pdf
| doi =
| id =
| isbn = 0-89791-570-4
| accessdate = 2008-10-17}}
*{{Cite book
| first = Jim
| last = Veitch
| author-link =
| author2-link =
| editor-last = Salus
| editor-first = Peter H
| editor2-last =
| editor2-first =
| contribution = A history and description of CLOS
| contribution-url =
| title = Handbook of programming languages
| volume = Volume IV, Functional and logic programming languages
| edition = first
| year = 1998
| pages = [https://archive.org/details/handbookofprogra0000unse/page/107 107–158]
| place = Indianapolis, IN
| publisher = Macmillan Technical Publishing
| url = https://archive.org/details/handbookofprogra0000unse/page/107
| doi =
| id =
| isbn = 1-57870-011-6
| postscript = <!--None-->
}}
*{{Cite book
|title= [[Structure and Interpretation of Computer Programs]]
|first= Harold
|last= Abelson
|author-link= Harold Abelson
|first2= Gerald Jay
|last2= Sussman
|author2-link= Gerald Jay Sussman
|first3= Julie
|last3= Sussman
|author3-link= Julie Sussman
|year= 1996
|edition= 2nd
|publisher= MIT Press
|isbn= 0-262-01153-0
|doi= }}
*[https://www.gnu.org/gnu/rms-lisp.html My Lisp Experiences and the Development of GNU Emacs], [[transcription (linguistics)|transcript]] of [[Richard Stallman]]'s speech, 28 October 2002, at the [[International Lisp Conference]]
*{{Cite book
|first= Paul
|last= Graham
|author-link= Paul Graham (computer programmer)
|title= [[Hackers & Painters| Hackers & Painters. Big Ideas from the Computer Age]]
|year= 2004
|publisher= O'Reilly
|isbn= 0-596-00662-4
|doi= }}
*{{Cite book
|editor-last= Berkeley
|editor-first= Edmund C.
|editor-link= Edmund Berkeley
|editor2-last= Bobrow
|editor2-first= Daniel G.
|editor2-link= Daniel G. Bobrow
|title= The Programming Language LISP: Its Operation and Applications
|url= http://www.softwarepreservation.org/projects/LISP/book/III_LispBook_Apr66.pdf
|date= March 1964
|publisher= MIT Press
|location= Cambridge, Massachusetts
|isbn=
|doi= }}
**Article largely based on the ''LISP - A Simple Introduction'' chapter: {{cite journal |last1=Berkeley |first1=Edmund C. |title=THE PROGRAMMING LANGUAGE LISP: AN INTRODUCTION AND APPRAISAL |journal=Computers and Automation |date=Sep 1964 |pages=[https://archive.org/details/bitsavers_computersA_6908895/page/n15 16]-23 |url=https://archive.org/details/bitsavers_computersA_6908895}}
*{{Cite book
|last= Weissman
|first= Clark
|title= LISP 1.5 Primer
|year= 1967
|url= http://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf
|publisher= Dickenson Publishing Company Inc.
|location= Belmont, California
|isbn=
|doi=}}
{{Refend}}
==External links==
{{Sister project links|wikt=Lisp|commons=Category:Lisp (programming language)|n=no|q=Lisp programming language|b=Subject:Lisp programming language|v=Topic:Lisp|s=Lambda Papers}}
;History
*[http://www-formal.stanford.edu/jmc/history/lisp/lisp.html History of Lisp] – [[John McCarthy (computer scientist)|John McCarthy]]'s history of 12 February 1979
*[https://web.archive.org/web/20050617031004/http://www8.informatik.uni-erlangen.de/html/lisp-enter.html Lisp History] – Herbert Stoyan's history compiled from the documents (acknowledged by McCarthy as more complete than his own, see: [http://www-formal.stanford.edu/jmc/history/ McCarthy's history links])
*[http://www.softwarepreservation.org/projects/LISP/ History of LISP at the Computer History Museum]
;Associations and meetings
*[http://www.alu.org/ Association of Lisp Users]
*[http://www.weitz.de/eclm2013/ European Common Lisp Meeting]
*[http://european-lisp-symposium.org/ European Lisp Symposium]
*[http://www.international-lisp-conference.org/ International Lisp Conference]
; Books and tutorials
*''[http://www.lisperati.com/casting.html Casting SPELs in Lisp]'', a comic-book style introductory tutorial
*''[http://paulgraham.com/onlisptext.html On Lisp]'', a free book by [[Paul Graham (computer programmer)|Paul Graham]]
*''[http://www.gigamonkeys.com/book/ Practical Common Lisp]'', freeware edition by Peter Seibel
* [http://leanpub.com/lispweb Lisp for the web]
* [http://landoflisp.com/ Land of Lisp]
* [http://letoverlambda.com/ Let over Lambda]
; Interviews
*[http://purl.umn.edu/107476 Oral history interview with John McCarthy] at [[Charles Babbage Institute]], University of Minnesota, Minneapolis. McCarthy discusses his role in the development of time-sharing at the Massachusetts Institute of Technology. He also describes his work in artificial intelligence (AI) funded by the Advanced Research Projects Agency, including logic-based AI (LISP) and robotics.
*[http://www.se-radio.net/2008/01/episode-84-dick-gabriel-on-lisp/ Interview] with [[Richard P. Gabriel]] (Podcast)
;Resources
*[http://www.cliki.net/ CLiki: the Common Lisp wiki]
*[https://web.archive.org/web/20160311102031/http://www.cl-user.net/asp/erw/sdataQIvH87hu8NU%24DM%3D%3D/sdataQo5Y-1Mh9urk The Common Lisp Directory] (via the [[Wayback Machine]]; archived from [https://web.archive.org/web/20080905110332/http://cl-user.net/ the original])
*[http://www.faqs.org/faqs/lisp-faq/ Lisp FAQ Index]
*[http://paste.lisp.org/ lisppaste]
*[http://planet.lisp.org/ Planet Lisp]
*[http://lispnews.wordpress.com/ Weekly Lisp News]
*{{Curlie|Computers/Programming/Languages/Lisp|Lisp}}
{{Lisp programming language}}
{{John McCarthy navbox}}
{{Programming languages}}
{{Authority control}}
{{DEFAULTSORT:Lisp Programming Language}}
[[Category:Lisp (programming language)| ]]
[[Category:Academic programming languages]]
[[Category:American inventions]]
[[Category:Articles with example Lisp code]]
[[Category:Dynamically typed programming languages]]
[[Category:Extensible syntax programming languages]]
[[Category:Functional languages]]
[[Category:Lisp programming language family| ]]
[[Category:Programming languages]]
[[Category:Programming languages created in 1958]]' |
Unified diff of changes made by edit (edit_diff) | '@@ -1,93 +1,2 @@
-{{redirect|LISP|the Internet protocol|Locator/Identifier Separation Protocol|the Japanese [[girl group]]|Lisp (group)|the speech impediment|Lisp}}
-{{short description|Programming language family}}
-{{Infobox programming language
-| name = Lisp
-| logo = Lisplogo.png
-| paradigm = [[multi-paradigm programming language|Multi-paradigm]]: [[functional programming|functional]], [[procedural programming|procedural]], [[Reflection (computer programming)|reflective]], [[metaprogramming|meta]]
-| released = {{Start date and age|1958}}
-| designer = [[John McCarthy (computer scientist)|John McCarthy]]
-| developer = [[Steve Russell (computer scientist)|Steve Russell]], Timothy P. Hart, and Mike Levin
-| latest release version =
-| latest release date =
-| turing-complete = Yes
-| typing = [[Dynamic typing|Dynamic]], [[Strong and weak typing|strong]]
-| implementations =
-| dialects = {{startflatlist}}
-*[[Arc (programming language)|Arc]]
-*[[AutoLISP]]
-*[[Clojure]]
-*[[Common Lisp]]
-*[[Emacs Lisp]]
-*[[EuLisp]]
-*[[Franz Lisp]]
-*[[Hy]]
-*[[Interlisp]]
-*[[ISLISP]]
-*[[LeLisp]]
-*[[LFE (programming language)|LFE]]
-*[[Maclisp]]
-*[[MDL (programming language)|MDL]]
-*[[newLISP]]
-*[[NIL (programming language)|NIL]]
-*[[Picolisp]]
-*[[Portable Standard Lisp]]
-*[[Racket (programming language)|Racket]]
-*[[RPL (programming language)|RPL]]
-*[[Scheme (programming language)|Scheme]]
-*[[Cadence SKILL|SKILL]]
-*[[Spice Lisp]]
-*[[T (programming language)|T]]
-*[[Zetalisp]]
-{{endflatlist}}
-| influenced by = [[Information Processing Language|IPL]]
-| influenced = {{startflatlist}}
-*[[CLIPS]]
-*[[CLU (programming language)|CLU]]
-*[[COWSEL]]
-*[[Dylan (programming language)|Dylan]]
-*[[Elixir (programming language)|Elixir]]
-*[[Forth (programming language)|Forth]]
-*[[Haskell (programming language)|Haskell]]
-*[[Io (programming language)|Io]]
-*[[Ioke (programming language)|Ioke]]
-*[[JavaScript]]
-*[[Julia (programming language)|Julia]]<ref name="Julia">{{cite web |url=http://julia.readthedocs.org/en/latest/manual/introduction/ |title=Introduction |work=The Julia Manual |publisher=Read the Docs |accessdate=2016-12-10 |url-status=dead |archiveurl=https://web.archive.org/web/20160408134008/http://julia.readthedocs.org/en/latest/manual/introduction/ |archivedate=2016-04-08 }}</ref>
-*[[Logo (programming language)|Logo]]
-*[[Lua (programming language)|Lua]]
-*[[ML (programming language)|ML]]
-*[[Nim (programming language)|Nim]]
-*[[Nu (programming language)|Nu]]
-*[[OPS5]]
-*[[Perl]]
-*[[POP-2]]/[[POP-11|11]]
-*[[Python (programming language)|Python]]
-*[[R (programming language)|R]]
-*[[Rebol]]
-*[[Ruby (programming language)|Ruby]]
-*[[Scala (programming language)|Scala]]
-*[[Swift (programming language)|Swift]]
-*[[Smalltalk]]
-*[[Tcl]]
-*[[Wolfram Language]]<ref name="Wolfram">{{cite web |url=https://www.wolfram.com/language/faq/ |title=Wolfram Language Q&A |publisher=Wolfram Research |accessdate=2016-12-10}}</ref>{{endflatlist}}
-}}
-
-'''Lisp''' (historically '''LISP''') is a family of [[programming language]]s with a long history and a distinctive, fully [[parenthesized]] [[Polish notation#Computer programming|prefix notation]].<ref>
-{{cite book
- | title = Milestones in computer science and information technology
- | author = Edwin D. Reilly
- | publisher = Greenwood Publishing Group
- | year = 2003
- | isbn = 978-1-57356-521-9
- | pages = 156–157
- | url = https://books.google.com/books?id=JTYPKxug49IC&pg=PA157
- }}</ref>
-Originally specified in 1958, Lisp is the second-oldest [[high-level programming language]] in widespread use today. Only [[Fortran]] is older, by one year.<ref>{{cite web|url=http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|archive-url=https://web.archive.org/web/20010727170154/http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|url-status=dead|archive-date=2001-07-27|quote=Lisp is a survivor, having been in use for about a quarter of a century. Among the active programming languages only Fortran has had a longer life.|title=SICP: Foreword}}</ref><ref>{{cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|title=Conclusions|access-date=2014-06-04|archive-url=https://web.archive.org/web/20140403021353/http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|archive-date=2014-04-03|url-status=dead}}</ref> Lisp has changed since its early days, and many [[Programming language dialect|dialects]] have existed over its history. Today, the best-known general-purpose Lisp dialects are [[Racket (programming language)|Racket]], [[Common Lisp]], [[Scheme (programming language)|Scheme]] and [[Clojure]].
-
-Lisp was originally created as a practical [[mathematical notation]] for [[computer program]]s, influenced by the notation of [[Alonzo Church]]'s [[lambda calculus]]. It quickly became the favored programming language for [[artificial intelligence]] (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in [[computer science]], including [[tree (data structure)|tree data structures]], [[garbage collection (computer science)|automatic storage management]], [[dynamic typing]], [[Conditional (computer programming)|conditionals]], [[higher-order function]]s, [[recursion (computer science)|recursion]], the [[Self-hosting (compilers)|self-hosting]] [[compiler]],<ref name="Graham">{{cite web |title=Revenge of the Nerds |author=Paul Graham |url=http://www.paulgraham.com/icad.html |accessdate=2013-03-14}}</ref> and the [[read–eval–print loop]].<ref>{{Cite book|url=http://www.informit.com/articles/article.aspx?p=1671639&seqNum=3|title=Influential Programming Languages, Part 4: Lisp|last=Chisnall|first=David|date=2011-01-12}}</ref>
-
-The name ''LISP'' derives from "LISt Processor".<ref name=ArtOfLisp>{{cite book|last1=Jones|first1=Robin|last2=Maynard|first2=Clive|last3=Stewart|first3=Ian|title=The Art of Lisp Programming|date=December 6, 2012|publisher=Springer Science & Business Media|isbn=9781447117193|page=2}}</ref> [[Linked list]]s are one of Lisp's major [[data structure]]s, and Lisp [[source code]] is made of lists. Thus, Lisp programs can manipulate source code as a data structure, giving rise to the [[macro (computer science)|macro]] systems that allow programmers to create new syntax or new [[domain-specific language]]s embedded in Lisp.
-
-The interchangeability of code and data gives Lisp its instantly recognizable syntax. All program code is written as ''[[s-expression]]s'', or parenthesized lists. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function {{Lisp2|f}} that takes three arguments would be called as {{Lisp2|(f arg1 arg2 arg3)}}.
-
==History==
{{Multiple image|image1 = John McCarthy Stanford.jpg|footer = [[John McCarthy (computer scientist)|John McCarthy]] (top) and [[Steve Russell (computer scientist)|Steve Russell]]|image2 = Steve Russell.jpg|direction = vertical}}
' |
New page size (new_size) | 70809 |
Old page size (old_size) | 77563 |
Size change in edit (edit_delta) | -6754 |
Lines added in edit (added_lines) | [] |
Lines removed in edit (removed_lines) | [
0 => '{{redirect|LISP|the Internet protocol|Locator/Identifier Separation Protocol|the Japanese [[girl group]]|Lisp (group)|the speech impediment|Lisp}}',
1 => '{{short description|Programming language family}}',
2 => '{{Infobox programming language',
3 => '| name = Lisp',
4 => '| logo = Lisplogo.png',
5 => '| paradigm = [[multi-paradigm programming language|Multi-paradigm]]: [[functional programming|functional]], [[procedural programming|procedural]], [[Reflection (computer programming)|reflective]], [[metaprogramming|meta]]',
6 => '| released = {{Start date and age|1958}}',
7 => '| designer = [[John McCarthy (computer scientist)|John McCarthy]]',
8 => '| developer = [[Steve Russell (computer scientist)|Steve Russell]], Timothy P. Hart, and Mike Levin',
9 => '| latest release version = ',
10 => '| latest release date = ',
11 => '| turing-complete = Yes',
12 => '| typing = [[Dynamic typing|Dynamic]], [[Strong and weak typing|strong]]',
13 => '| implementations = ',
14 => '| dialects = {{startflatlist}}',
15 => '*[[Arc (programming language)|Arc]]',
16 => '*[[AutoLISP]]',
17 => '*[[Clojure]]',
18 => '*[[Common Lisp]]',
19 => '*[[Emacs Lisp]]',
20 => '*[[EuLisp]]',
21 => '*[[Franz Lisp]]',
22 => '*[[Hy]]',
23 => '*[[Interlisp]]',
24 => '*[[ISLISP]]',
25 => '*[[LeLisp]] ',
26 => '*[[LFE (programming language)|LFE]] ',
27 => '*[[Maclisp]] ',
28 => '*[[MDL (programming language)|MDL]] ',
29 => '*[[newLISP]] ',
30 => '*[[NIL (programming language)|NIL]] ',
31 => '*[[Picolisp]] ',
32 => '*[[Portable Standard Lisp]] ',
33 => '*[[Racket (programming language)|Racket]] ',
34 => '*[[RPL (programming language)|RPL]] ',
35 => '*[[Scheme (programming language)|Scheme]] ',
36 => '*[[Cadence SKILL|SKILL]] ',
37 => '*[[Spice Lisp]] ',
38 => '*[[T (programming language)|T]]',
39 => '*[[Zetalisp]]',
40 => '{{endflatlist}}',
41 => '| influenced by = [[Information Processing Language|IPL]]',
42 => '| influenced = {{startflatlist}}',
43 => '*[[CLIPS]] ',
44 => '*[[CLU (programming language)|CLU]] ',
45 => '*[[COWSEL]] ',
46 => '*[[Dylan (programming language)|Dylan]] ',
47 => '*[[Elixir (programming language)|Elixir]] ',
48 => '*[[Forth (programming language)|Forth]] ',
49 => '*[[Haskell (programming language)|Haskell]] ',
50 => '*[[Io (programming language)|Io]] ',
51 => '*[[Ioke (programming language)|Ioke]] ',
52 => '*[[JavaScript]] ',
53 => '*[[Julia (programming language)|Julia]]<ref name="Julia">{{cite web |url=http://julia.readthedocs.org/en/latest/manual/introduction/ |title=Introduction |work=The Julia Manual |publisher=Read the Docs |accessdate=2016-12-10 |url-status=dead |archiveurl=https://web.archive.org/web/20160408134008/http://julia.readthedocs.org/en/latest/manual/introduction/ |archivedate=2016-04-08 }}</ref>',
54 => '*[[Logo (programming language)|Logo]] ',
55 => '*[[Lua (programming language)|Lua]] ',
56 => '*[[ML (programming language)|ML]] ',
57 => '*[[Nim (programming language)|Nim]] ',
58 => '*[[Nu (programming language)|Nu]] ',
59 => '*[[OPS5]] ',
60 => '*[[Perl]] ',
61 => '*[[POP-2]]/[[POP-11|11]] ',
62 => '*[[Python (programming language)|Python]] ',
63 => '*[[R (programming language)|R]] ',
64 => '*[[Rebol]] ',
65 => '*[[Ruby (programming language)|Ruby]] ',
66 => '*[[Scala (programming language)|Scala]] ',
67 => '*[[Swift (programming language)|Swift]]',
68 => '*[[Smalltalk]] ',
69 => '*[[Tcl]] ',
70 => '*[[Wolfram Language]]<ref name="Wolfram">{{cite web |url=https://www.wolfram.com/language/faq/ |title=Wolfram Language Q&A |publisher=Wolfram Research |accessdate=2016-12-10}}</ref>{{endflatlist}}',
71 => '}}',
72 => '',
73 => ''''Lisp''' (historically '''LISP''') is a family of [[programming language]]s with a long history and a distinctive, fully [[parenthesized]] [[Polish notation#Computer programming|prefix notation]].<ref>',
74 => '{{cite book',
75 => ' | title = Milestones in computer science and information technology',
76 => ' | author = Edwin D. Reilly',
77 => ' | publisher = Greenwood Publishing Group',
78 => ' | year = 2003',
79 => ' | isbn = 978-1-57356-521-9',
80 => ' | pages = 156–157',
81 => ' | url = https://books.google.com/books?id=JTYPKxug49IC&pg=PA157',
82 => ' }}</ref>',
83 => 'Originally specified in 1958, Lisp is the second-oldest [[high-level programming language]] in widespread use today. Only [[Fortran]] is older, by one year.<ref>{{cite web|url=http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|archive-url=https://web.archive.org/web/20010727170154/http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html|url-status=dead|archive-date=2001-07-27|quote=Lisp is a survivor, having been in use for about a quarter of a century. Among the active programming languages only Fortran has had a longer life.|title=SICP: Foreword}}</ref><ref>{{cite web|url=http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|title=Conclusions|access-date=2014-06-04|archive-url=https://web.archive.org/web/20140403021353/http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000|archive-date=2014-04-03|url-status=dead}}</ref> Lisp has changed since its early days, and many [[Programming language dialect|dialects]] have existed over its history. Today, the best-known general-purpose Lisp dialects are [[Racket (programming language)|Racket]], [[Common Lisp]], [[Scheme (programming language)|Scheme]] and [[Clojure]].',
84 => '',
85 => 'Lisp was originally created as a practical [[mathematical notation]] for [[computer program]]s, influenced by the notation of [[Alonzo Church]]'s [[lambda calculus]]. It quickly became the favored programming language for [[artificial intelligence]] (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in [[computer science]], including [[tree (data structure)|tree data structures]], [[garbage collection (computer science)|automatic storage management]], [[dynamic typing]], [[Conditional (computer programming)|conditionals]], [[higher-order function]]s, [[recursion (computer science)|recursion]], the [[Self-hosting (compilers)|self-hosting]] [[compiler]],<ref name="Graham">{{cite web |title=Revenge of the Nerds |author=Paul Graham |url=http://www.paulgraham.com/icad.html |accessdate=2013-03-14}}</ref> and the [[read–eval–print loop]].<ref>{{Cite book|url=http://www.informit.com/articles/article.aspx?p=1671639&seqNum=3|title=Influential Programming Languages, Part 4: Lisp|last=Chisnall|first=David|date=2011-01-12}}</ref>',
86 => '',
87 => 'The name ''LISP'' derives from "LISt Processor".<ref name=ArtOfLisp>{{cite book|last1=Jones|first1=Robin|last2=Maynard|first2=Clive|last3=Stewart|first3=Ian|title=The Art of Lisp Programming|date=December 6, 2012|publisher=Springer Science & Business Media|isbn=9781447117193|page=2}}</ref> [[Linked list]]s are one of Lisp's major [[data structure]]s, and Lisp [[source code]] is made of lists. Thus, Lisp programs can manipulate source code as a data structure, giving rise to the [[macro (computer science)|macro]] systems that allow programmers to create new syntax or new [[domain-specific language]]s embedded in Lisp.',
88 => '',
89 => 'The interchangeability of code and data gives Lisp its instantly recognizable syntax. All program code is written as ''[[s-expression]]s'', or parenthesized lists. A function call or syntactic form is written as a list with the function or operator's name first, and the arguments following; for instance, a function {{Lisp2|f}} that takes three arguments would be called as {{Lisp2|(f arg1 arg2 arg3)}}.',
90 => ''
] |
All external links added in the edit (added_links) | [] |
All external links removed in the edit (removed_links) | [
0 => 'http://julia.readthedocs.org/en/latest/manual/introduction/',
1 => 'http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html',
2 => 'http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000',
3 => 'http://www.informit.com/articles/article.aspx?p=1671639&seqNum=3',
4 => 'http://www.paulgraham.com/icad.html',
5 => 'https://books.google.com/books?id=JTYPKxug49IC&pg=PA157',
6 => 'https://web.archive.org/web/20010727170154/http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html',
7 => 'https://web.archive.org/web/20140403021353/http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000',
8 => 'https://web.archive.org/web/20160408134008/http://julia.readthedocs.org/en/latest/manual/introduction/',
9 => 'https://www.wolfram.com/language/faq/'
] |
All external links in the new text (all_links) | [
0 => 'https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html',
1 => 'http://www-formal.stanford.edu/jmc/recursive.html',
2 => 'http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf',
3 => 'http://jmc.stanford.edu/articles/lisp/lisp.pdf',
4 => 'http://www-formal.stanford.edu/jmc/history/lisp/node2.html',
5 => 'ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf',
6 => 'https://archive.org/details/lisp15programmer00john',
7 => 'http://groups.google.com/group/alt.folklore.computers/browse_thread/thread/6e5602ce733d0ec/17597705ae289112',
8 => 'news:alt.folklore.computers',
9 => 'news:84950@tut.cis.ohio-state.edu',
10 => 'https://web.archive.org/web/20100717111134/http://history.siam.org/sup/Fox_1960_LISP.pdf',
11 => 'http://history.siam.org/sup/Fox_1960_LISP.pdf',
12 => 'http://www.softwarepreservation.org/projects/LISP/stanford/SAILON-28.6.pdf',
13 => 'https://web.archive.org/web/20071214064433/http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt',
14 => 'http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt',
15 => 'https://web.archive.org/web/20060602134835/http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf',
16 => 'http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf',
17 => 'https://hal.archives-ouvertes.fr/file/index/docid/70041/filename/RT-0126.pdf',
18 => 'https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node6.html',
19 => 'https://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/faq-doc-13.html',
20 => 'http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22987',
21 => 'http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44338',
22 => 'http://www.nhplace.com/kent/CL/x3j13-86-020.html',
23 => 'https://web.archive.org/web/20061004031130/http://wiki.alu.org/The_Road_To_Lisp_Survey',
24 => 'http://wiki.alu.org/The_Road_To_Lisp_Survey',
25 => 'http://www.faqs.org/docs/artu/ch14s05.html',
26 => 'https://web.archive.org/web/20120421181340/http://common-lisp.net/~dlw/LispSurvey.html#',
27 => 'http://common-lisp.net/~dlw/LispSurvey.html',
28 => 'http://www.lisp50.org/',
29 => 'http://www.schemers.org/Documents/Standards/R5RS/',
30 => 'http://cemerick.com/2009/03/24/why-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program/',
31 => 'http://mitadmissions.org/blogs/entry/the_end_of_an_era_1',
32 => 'https://www.eecs.mit.edu/academics-admissions/undergraduate-programs',
33 => 'https://www.eecs.mit.edu/news-events/announcements/mitx-introductory-python-course-hits-12-million-enrollments',
34 => 'https://www.cliki.net/Clasp',
35 => 'https://common-lisp.net/project/armedbear/',
36 => 'https://common-lisp.net/~dlw/LispSurvey.html',
37 => 'https://web.archive.org/web/20180622083812/https://common-lisp.net/~dlw/LispSurvey.html#',
38 => 'https://www.cliki.net/Common+Lisp+implementation',
39 => 'http://www.infoq.com/articles/in-depth-look-clojure-collections',
40 => 'https://clojure.org/about/rationale',
41 => 'http://www.gimp.org/docs/script-fu-update.html',
42 => 'http://sawfish.wikia.com/wiki/Librep',
43 => 'https://standards.ieee.org/standard/1178-1990.html',
44 => 'http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en',
45 => 'http://web.media.mit.edu/~lieber/Lieberary/GC/Realtime/Realtime.html',
46 => '//citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.8633',
47 => '//doi.org/10.1145%2F358141.358147',
48 => 'http://www.cs.utexas.edu/~EWD/transcriptions/EWD03xx/EWD340.html',
49 => 'https://www.linkedin.com/pulse/look-clojure-lisp-resurgence-todd-towles',
50 => 'http://www.catb.org/~esr/jargon/html/L/LISP.html',
51 => 'https://www.pearson.com/us/higher-education/product/Sebesta-Concepts-of-Programming-Languages-10th-Edition/9780131395312.html',
52 => 'http://www.cs.washington.edu/education/courses/cse341/04wi/lectures/14-scheme-quote.html',
53 => 'http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf',
54 => 'https://web.archive.org/web/20130603114956/http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf',
55 => 'https://www.gnu.org/software/emacs/manual/html_node/cl/Time-of-Evaluation.html',
56 => 'http://www.lispworks.com/documentation/HyperSpec/Body/03_bbc.htm',
57 => 'http://www.lispworks.com/documentation/HyperSpec/Front/index.htm',
58 => 'http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf',
59 => 'ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf',
60 => 'https://www.wikidata.org/wiki/Q132874',
61 => 'http://paulgraham.com/bel.html',
62 => 'http://www-formal.stanford.edu/jmc/history/lisp/node3.html',
63 => 'http://www.dreamsongs.com/NewFiles/HOPL2-Uncut.pdf',
64 => 'https://archive.org/details/handbookofprogra0000unse/page/107',
65 => 'https://www.gnu.org/gnu/rms-lisp.html',
66 => 'http://www.softwarepreservation.org/projects/LISP/book/III_LispBook_Apr66.pdf',
67 => 'https://archive.org/details/bitsavers_computersA_6908895',
68 => 'https://archive.org/details/bitsavers_computersA_6908895/page/n15',
69 => 'http://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf',
70 => 'http://www-formal.stanford.edu/jmc/history/lisp/lisp.html',
71 => 'https://web.archive.org/web/20050617031004/http://www8.informatik.uni-erlangen.de/html/lisp-enter.html',
72 => 'http://www-formal.stanford.edu/jmc/history/',
73 => 'http://www.softwarepreservation.org/projects/LISP/',
74 => 'http://www.alu.org/',
75 => 'http://www.weitz.de/eclm2013/',
76 => 'http://european-lisp-symposium.org/',
77 => 'http://www.international-lisp-conference.org/',
78 => 'http://www.lisperati.com/casting.html',
79 => 'http://paulgraham.com/onlisptext.html',
80 => 'http://www.gigamonkeys.com/book/',
81 => 'http://leanpub.com/lispweb',
82 => 'http://landoflisp.com/',
83 => 'http://letoverlambda.com/',
84 => 'http://purl.umn.edu/107476',
85 => 'http://www.se-radio.net/2008/01/episode-84-dick-gabriel-on-lisp/',
86 => 'http://www.cliki.net/',
87 => 'https://web.archive.org/web/20160311102031/http://www.cl-user.net/asp/erw/sdataQIvH87hu8NU$DM==/sdataQo5Y-1Mh9urk',
88 => 'https://web.archive.org/web/20080905110332/http://cl-user.net/',
89 => 'http://www.faqs.org/faqs/lisp-faq/',
90 => 'http://paste.lisp.org/',
91 => 'http://planet.lisp.org/',
92 => 'http://lispnews.wordpress.com/',
93 => 'https://curlie.org/Computers/Programming/Languages/Lisp',
94 => 'http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?action=display&authority_id=XX535292',
95 => 'https://catalogue.bnf.fr/ark:/12148/cb11934831x',
96 => 'https://data.bnf.fr/ark:/12148/cb11934831x',
97 => 'https://d-nb.info/gnd/4035918-9',
98 => 'https://id.loc.gov/authorities/subjects/sh85077449',
99 => 'https://www.idref.fr/027270394'
] |
Links in the page, before the edit (old_links) | [
0 => '//citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.8633',
1 => '//citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.8633',
2 => '//doi.org/10.1145%2F358141.358147',
3 => '//doi.org/10.1145%2F358141.358147',
4 => 'ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf',
5 => 'ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf',
6 => 'http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?action=display&authority_id=XX535292',
7 => 'http://cemerick.com/2009/03/24/why-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program/',
8 => 'http://common-lisp.net/~dlw/LispSurvey.html',
9 => 'http://european-lisp-symposium.org/',
10 => 'http://groups.google.com/group/alt.folklore.computers/browse_thread/thread/6e5602ce733d0ec/17597705ae289112',
11 => 'http://history.siam.org/sup/Fox_1960_LISP.pdf',
12 => 'http://jmc.stanford.edu/articles/lisp/lisp.pdf',
13 => 'http://julia.readthedocs.org/en/latest/manual/introduction/',
14 => 'http://landoflisp.com/',
15 => 'http://leanpub.com/lispweb',
16 => 'http://letoverlambda.com/',
17 => 'http://lispnews.wordpress.com/',
18 => 'http://mitadmissions.org/blogs/entry/the_end_of_an_era_1',
19 => 'http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html',
20 => 'http://paste.lisp.org/',
21 => 'http://paulgraham.com/bel.html',
22 => 'http://paulgraham.com/onlisptext.html',
23 => 'http://planet.lisp.org/',
24 => 'http://purl.umn.edu/107476',
25 => 'http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf',
26 => 'http://sawfish.wikia.com/wiki/Librep',
27 => 'http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en',
28 => 'http://web.media.mit.edu/~lieber/Lieberary/GC/Realtime/Realtime.html',
29 => 'http://wiki.alu.org/The_Road_To_Lisp_Survey',
30 => 'http://www-formal.stanford.edu/jmc/history/lisp/node2.html',
31 => 'http://www-formal.stanford.edu/jmc/history/lisp/node3.html',
32 => 'http://www-formal.stanford.edu/jmc/history/lisp/lisp.html',
33 => 'http://www-formal.stanford.edu/jmc/history/',
34 => 'http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000',
35 => 'http://www-formal.stanford.edu/jmc/recursive.html',
36 => 'http://www.alu.org/',
37 => 'http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf',
38 => 'http://www.catb.org/~esr/jargon/html/L/LISP.html',
39 => 'http://www.cliki.net/',
40 => 'http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf',
41 => 'http://www.cs.utexas.edu/~EWD/transcriptions/EWD03xx/EWD340.html',
42 => 'http://www.cs.washington.edu/education/courses/cse341/04wi/lectures/14-scheme-quote.html',
43 => 'http://www.dreamsongs.com/NewFiles/HOPL2-Uncut.pdf',
44 => 'http://www.faqs.org/docs/artu/ch14s05.html',
45 => 'http://www.faqs.org/faqs/lisp-faq/',
46 => 'http://www.gigamonkeys.com/book/',
47 => 'http://www.gimp.org/docs/script-fu-update.html',
48 => 'http://www.infoq.com/articles/in-depth-look-clojure-collections',
49 => 'http://www.informit.com/articles/article.aspx?p=1671639&seqNum=3',
50 => 'http://www.international-lisp-conference.org/',
51 => 'http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22987',
52 => 'http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44338',
53 => 'http://www.lisp50.org/',
54 => 'http://www.lisperati.com/casting.html',
55 => 'http://www.lispworks.com/documentation/HyperSpec/Body/03_bbc.htm',
56 => 'http://www.lispworks.com/documentation/HyperSpec/Front/index.htm',
57 => 'http://www.nhplace.com/kent/CL/x3j13-86-020.html',
58 => 'http://www.paulgraham.com/icad.html',
59 => 'http://www.schemers.org/Documents/Standards/R5RS/',
60 => 'http://www.se-radio.net/2008/01/episode-84-dick-gabriel-on-lisp/',
61 => 'http://www.softwarepreservation.org/projects/LISP/book/III_LispBook_Apr66.pdf',
62 => 'http://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf',
63 => 'http://www.softwarepreservation.org/projects/LISP/',
64 => 'http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf',
65 => 'http://www.softwarepreservation.org/projects/LISP/stanford/SAILON-28.6.pdf',
66 => 'http://www.weitz.de/eclm2013/',
67 => 'http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt',
68 => 'https://archive.org/details/bitsavers_computersA_6908895/page/n15',
69 => 'https://archive.org/details/bitsavers_computersA_6908895',
70 => 'https://archive.org/details/handbookofprogra0000unse/page/107',
71 => 'https://archive.org/details/lisp15programmer00john',
72 => 'https://books.google.com/books?id=JTYPKxug49IC&pg=PA157',
73 => 'https://catalogue.bnf.fr/ark:/12148/cb11934831x',
74 => 'https://clojure.org/about/rationale',
75 => 'https://common-lisp.net/project/armedbear/',
76 => 'https://common-lisp.net/~dlw/LispSurvey.html',
77 => 'https://curlie.org/Computers/Programming/Languages/Lisp',
78 => 'https://d-nb.info/gnd/4035918-9',
79 => 'https://data.bnf.fr/ark:/12148/cb11934831x',
80 => 'https://hal.archives-ouvertes.fr/file/index/docid/70041/filename/RT-0126.pdf',
81 => 'https://id.loc.gov/authorities/subjects/sh85077449',
82 => 'https://standards.ieee.org/standard/1178-1990.html',
83 => 'https://web.archive.org/web/20010727170154/http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-5.html',
84 => 'https://web.archive.org/web/20050617031004/http://www8.informatik.uni-erlangen.de/html/lisp-enter.html',
85 => 'https://web.archive.org/web/20060602134835/http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf',
86 => 'https://web.archive.org/web/20061004031130/http://wiki.alu.org/The_Road_To_Lisp_Survey',
87 => 'https://web.archive.org/web/20071214064433/http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt',
88 => 'https://web.archive.org/web/20080905110332/http://cl-user.net/',
89 => 'https://web.archive.org/web/20100717111134/http://history.siam.org/sup/Fox_1960_LISP.pdf',
90 => 'https://web.archive.org/web/20120421181340/http://common-lisp.net/~dlw/LispSurvey.html#',
91 => 'https://web.archive.org/web/20130603114956/http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf',
92 => 'https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html',
93 => 'https://web.archive.org/web/20140403021353/http://www-formal.stanford.edu/jmc/history/lisp/node6.html#SECTION00060000000000000000',
94 => 'https://web.archive.org/web/20160311102031/http://www.cl-user.net/asp/erw/sdataQIvH87hu8NU$DM==/sdataQo5Y-1Mh9urk',
95 => 'https://web.archive.org/web/20160408134008/http://julia.readthedocs.org/en/latest/manual/introduction/',
96 => 'https://web.archive.org/web/20180622083812/https://common-lisp.net/~dlw/LispSurvey.html#',
97 => 'https://www.cliki.net/Clasp',
98 => 'https://www.cliki.net/Common+Lisp+implementation',
99 => 'https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node6.html',
100 => 'https://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/faq-doc-13.html',
101 => 'https://www.eecs.mit.edu/academics-admissions/undergraduate-programs',
102 => 'https://www.eecs.mit.edu/news-events/announcements/mitx-introductory-python-course-hits-12-million-enrollments',
103 => 'https://www.gnu.org/gnu/rms-lisp.html',
104 => 'https://www.gnu.org/software/emacs/manual/html_node/cl/Time-of-Evaluation.html',
105 => 'https://www.idref.fr/027270394',
106 => 'https://www.linkedin.com/pulse/look-clojure-lisp-resurgence-todd-towles',
107 => 'https://www.pearson.com/us/higher-education/product/Sebesta-Concepts-of-Programming-Languages-10th-Edition/9780131395312.html',
108 => 'https://www.wikidata.org/wiki/Q132874',
109 => 'https://www.wolfram.com/language/faq/',
110 => 'news:84950@tut.cis.ohio-state.edu',
111 => 'news:alt.folklore.computers'
] |
Parsed HTML source of the new revision (new_html) | '<div class="mw-parser-output"><div id="toc" class="toc" role="navigation" aria-labelledby="mw-toc-heading"><input type="checkbox" role="button" id="toctogglecheckbox" class="toctogglecheckbox" style="display:none" /><div class="toctitle" lang="en" dir="ltr"><h2 id="mw-toc-heading">Contents</h2><span class="toctogglespan"><label class="toctogglelabel" for="toctogglecheckbox"></label></span></div>
<ul>
<li class="toclevel-1 tocsection-1"><a href="#History"><span class="tocnumber">1</span> <span class="toctext">History</span></a>
<ul>
<li class="toclevel-2 tocsection-2"><a href="#Timeline"><span class="tocnumber">1.1</span> <span class="toctext">Timeline</span></a></li>
<li class="toclevel-2 tocsection-3"><a href="#Connection_to_artificial_intelligence"><span class="tocnumber">1.2</span> <span class="toctext">Connection to artificial intelligence</span></a></li>
<li class="toclevel-2 tocsection-4"><a href="#Genealogy_and_variants"><span class="tocnumber">1.3</span> <span class="toctext">Genealogy and variants</span></a>
<ul>
<li class="toclevel-3 tocsection-5"><a href="#Historically_significant_dialects"><span class="tocnumber">1.3.1</span> <span class="toctext">Historically significant dialects</span></a></li>
</ul>
</li>
<li class="toclevel-2 tocsection-6"><a href="#2000_to_present"><span class="tocnumber">1.4</span> <span class="toctext">2000 to present</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-7"><a href="#Major_dialects"><span class="tocnumber">2</span> <span class="toctext">Major dialects</span></a>
<ul>
<li class="toclevel-2 tocsection-8"><a href="#Standardized_dialects"><span class="tocnumber">2.1</span> <span class="toctext">Standardized dialects</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-9"><a href="#Language_innovations"><span class="tocnumber">3</span> <span class="toctext">Language innovations</span></a></li>
<li class="toclevel-1 tocsection-10"><a href="#Syntax_and_semantics"><span class="tocnumber">4</span> <span class="toctext">Syntax and semantics</span></a>
<ul>
<li class="toclevel-2 tocsection-11"><a href="#Symbolic_expressions_(S-expressions)"><span class="tocnumber">4.1</span> <span class="toctext">Symbolic expressions (S-expressions)</span></a></li>
<li class="toclevel-2 tocsection-12"><a href="#Lists"><span class="tocnumber">4.2</span> <span class="toctext">Lists</span></a></li>
<li class="toclevel-2 tocsection-13"><a href="#Operators"><span class="tocnumber">4.3</span> <span class="toctext">Operators</span></a></li>
<li class="toclevel-2 tocsection-14"><a href="#Lambda_expressions_and_function_definition"><span class="tocnumber">4.4</span> <span class="toctext">Lambda expressions and function definition</span></a></li>
<li class="toclevel-2 tocsection-15"><a href="#Atoms"><span class="tocnumber">4.5</span> <span class="toctext">Atoms</span></a></li>
<li class="toclevel-2 tocsection-16"><a href="#Conses_and_lists"><span class="tocnumber">4.6</span> <span class="toctext">Conses and lists</span></a>
<ul>
<li class="toclevel-3 tocsection-17"><a href="#S-expressions_represent_lists"><span class="tocnumber">4.6.1</span> <span class="toctext">S-expressions represent lists</span></a></li>
<li class="toclevel-3 tocsection-18"><a href="#List-processing_procedures"><span class="tocnumber">4.6.2</span> <span class="toctext">List-processing procedures</span></a></li>
<li class="toclevel-3 tocsection-19"><a href="#Shared_structure"><span class="tocnumber">4.6.3</span> <span class="toctext">Shared structure</span></a></li>
</ul>
</li>
<li class="toclevel-2 tocsection-20"><a href="#Self-evaluating_forms_and_quoting"><span class="tocnumber">4.7</span> <span class="toctext">Self-evaluating forms and quoting</span></a></li>
<li class="toclevel-2 tocsection-21"><a href="#Scope_and_closure"><span class="tocnumber">4.8</span> <span class="toctext">Scope and closure</span></a></li>
<li class="toclevel-2 tocsection-22"><a href="#List_structure_of_program_code;_exploitation_by_macros_and_compilers"><span class="tocnumber">4.9</span> <span class="toctext">List structure of program code; exploitation by macros and compilers</span></a></li>
<li class="toclevel-2 tocsection-23"><a href="#Evaluation_and_the_read–eval–print_loop"><span class="tocnumber">4.10</span> <span class="toctext">Evaluation and the read–eval–print loop</span></a></li>
<li class="toclevel-2 tocsection-24"><a href="#Control_structures"><span class="tocnumber">4.11</span> <span class="toctext">Control structures</span></a></li>
</ul>
</li>
<li class="toclevel-1 tocsection-25"><a href="#Examples"><span class="tocnumber">5</span> <span class="toctext">Examples</span></a></li>
<li class="toclevel-1 tocsection-26"><a href="#Object_systems"><span class="tocnumber">6</span> <span class="toctext">Object systems</span></a></li>
<li class="toclevel-1 tocsection-27"><a href="#See_also"><span class="tocnumber">7</span> <span class="toctext">See also</span></a></li>
<li class="toclevel-1 tocsection-28"><a href="#References"><span class="tocnumber">8</span> <span class="toctext">References</span></a></li>
<li class="toclevel-1 tocsection-29"><a href="#Further_reading"><span class="tocnumber">9</span> <span class="toctext">Further reading</span></a></li>
<li class="toclevel-1 tocsection-30"><a href="#External_links"><span class="tocnumber">10</span> <span class="toctext">External links</span></a></li>
</ul>
</div>
<h2><span class="mw-headline" id="History">History</span></h2>
<style data-mw-deduplicate="TemplateStyles:r923042769/mw-parser-output/.tmulti">.mw-parser-output .tmulti .thumbinner{display:flex;flex-direction:column}.mw-parser-output .tmulti .trow{display:flex;flex-direction:row;clear:left;flex-wrap:wrap;width:100%;box-sizing:border-box}.mw-parser-output .tmulti .tsingle{margin:1px;float:left}.mw-parser-output .tmulti .theader{clear:both;font-weight:bold;text-align:center;align-self:center;background-color:transparent;width:100%}.mw-parser-output .tmulti .thumbcaption{text-align:left;background-color:transparent}.mw-parser-output .tmulti .thumbcaption-center{text-align:center;background-color:transparent}.mw-parser-output .tmulti .text-align-left{text-align:left}.mw-parser-output .tmulti .text-align-right{text-align:right}.mw-parser-output .tmulti .text-align-center{text-align:center}@media all and (max-width:720px){.mw-parser-output .tmulti .thumbinner{width:100%!important;box-sizing:border-box;max-width:none!important;align-items:center}.mw-parser-output .tmulti .trow{justify-content:center}.mw-parser-output .tmulti .tsingle{float:none!important;max-width:100%!important;box-sizing:border-box;text-align:center}.mw-parser-output .tmulti .thumbcaption{text-align:center}}</style><div class="thumb tmulti tright"><div class="thumbinner" style="width:204px;max-width:204px"><div class="trow"><div class="tsingle" style="width:202px;max-width:202px"><div class="thumbimage"><a href="/wiki/File:John_McCarthy_Stanford.jpg" class="image"><img alt="" src="/media/wikipedia/commons/thumb/4/49/John_McCarthy_Stanford.jpg/200px-John_McCarthy_Stanford.jpg" decoding="async" width="200" height="232" data-file-width="2013" data-file-height="2332" /></a></div></div></div><div class="trow"><div class="tsingle" style="width:202px;max-width:202px"><div class="thumbimage"><a href="/wiki/File:Steve_Russell.jpg" class="image"><img alt="" src="/media/wikipedia/commons/thumb/7/7b/Steve_Russell.jpg/200px-Steve_Russell.jpg" decoding="async" width="200" height="331" data-file-width="711" data-file-height="1178" /></a></div></div></div><div class="trow"><div class="thumbcaption" style="background-color:transparent"><a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">John McCarthy</a> (top) and <a href="/wiki/Steve_Russell_(computer_scientist)" title="Steve Russell (computer scientist)">Steve Russell</a></div></div></div></div>
<p><a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">John McCarthy</a> developed Lisp in 1958 while he was at the <a href="/wiki/Massachusetts_Institute_of_Technology" title="Massachusetts Institute of Technology">Massachusetts Institute of Technology</a> (MIT). McCarthy published its design in a paper in <i><a href="/wiki/Communications_of_the_ACM" title="Communications of the ACM">Communications of the ACM</a></i> in 1960, entitled "Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I".<sup id="cite_ref-MCCARTHY_1-0" class="reference"><a href="#cite_note-MCCARTHY-1">[1]</a></sup> He showed that with a few simple operators and a notation for anonymous functions borrowed from Church, one can build a <a href="/wiki/Turing_completeness" title="Turing completeness">Turing-complete</a> language for algorithms.
</p><p><a href="/wiki/Information_Processing_Language" title="Information Processing Language">Information Processing Language</a> was the first AI language, from 1955 or 1956, and already included many of the concepts, such as list-processing and recursion, which came to be used in Lisp.
</p><p>McCarthy's original notation used bracketed "<a href="/wiki/M-expression" title="M-expression">M-expressions</a>" that would be translated into <a href="/wiki/S-expression" title="S-expression">S-expressions</a>. As an example, the M-expression <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">car[cons[A,B]]</span></code> is equivalent to the S-expression <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nb">car</span> <span class="p">(</span><span class="nb">cons</span> <span class="nv">A</span> <span class="nv">B</span><span class="p">))</span></code>. Once Lisp was implemented, programmers rapidly chose to use S-expressions, and M-expressions were abandoned. M-expressions surfaced again with short-lived attempts of <a href="/wiki/MLisp" title="MLisp">MLisp</a><sup id="cite_ref-SMITH_2-0" class="reference"><a href="#cite_note-SMITH-2">[2]</a></sup> by <a href="/w/index.php?title=Horace_Enea&action=edit&redlink=1" class="new" title="Horace Enea (page does not exist)">Horace Enea</a> and <a href="/wiki/CGOL" title="CGOL">CGOL</a> by <a href="/wiki/Vaughan_Pratt" title="Vaughan Pratt">Vaughan Pratt</a>.
</p><p>Lisp was first implemented by <a href="/wiki/Steve_Russell_(computer_scientist)" title="Steve Russell (computer scientist)">Steve Russell</a> on an <a href="/wiki/IBM_704" title="IBM 704">IBM 704</a> computer using <a href="/wiki/Punched_card" title="Punched card">punched cards</a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3">[3]</a></sup> Russell had read McCarthy's paper and realized (to McCarthy's surprise) that the Lisp <i>eval</i> function could be implemented in <a href="/wiki/Machine_code" title="Machine code">machine code</a>.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4">[4]</a></sup> The result was a working Lisp interpreter which could be used to run Lisp programs, or more properly, "evaluate Lisp expressions".
</p><p>Two <a href="/wiki/Assembly_language_macros" class="mw-redirect" title="Assembly language macros">assembly language macros</a> for the <a href="/wiki/IBM_704" title="IBM 704">IBM 704</a> became the primitive operations for decomposing lists: <a href="/wiki/Car_and_cdr" class="mw-redirect" title="Car and cdr"><code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">car</span></code></a> (<i>Contents of the Address part of Register</i> number) and <a href="/wiki/Car_and_cdr" class="mw-redirect" title="Car and cdr"><code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cdr</span></code></a> (<i>Contents of the Decrement part of Register</i> number),<sup id="cite_ref-PREHISTORY_5-0" class="reference"><a href="#cite_note-PREHISTORY-5">[5]</a></sup> where "register" is used to refer to <a href="/wiki/Processor_register" title="Processor register">registers</a> of the computer's <a href="/wiki/Central_processing_unit" title="Central processing unit">central processing unit</a> (CPU). Lisp dialects still use <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">car</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cdr</span></code> (<span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="'k' in 'kind'">k</span><span title="/ɑːr/: 'ar' in 'far'">ɑːr</span></span>/</a></span></span> and <span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="/ˈ/: primary stress follows">ˈ</span><span title="'k' in 'kind'">k</span><span title="/ʊ/: 'u' in 'push'">ʊ</span><span title="'d' in 'dye'">d</span><span title="/ər/: 'er' in 'letter'">ər</span></span>/</a></span></span>) for the operations that return the first item in a list and the rest of the list, respectively.
</p><p>The first complete Lisp compiler, written in Lisp, was implemented in 1962 by Tim Hart and Mike Levin at MIT.<sup id="cite_ref-LEVIN_6-0" class="reference"><a href="#cite_note-LEVIN-6">[6]</a></sup> This compiler introduced the Lisp model of incremental compilation, in which compiled and interpreted functions can intermix freely. The language used in Hart and Levin's memo is much closer to modern Lisp style than McCarthy's earlier code.
</p><p>The first <a href="/wiki/Garbage_collection_(computer_science)" title="Garbage collection (computer science)">garbage collection</a> routines were developed by MIT graduate student <a href="/w/index.php?title=Daniel_Edwards_(programmer)&action=edit&redlink=1" class="new" title="Daniel Edwards (programmer) (page does not exist)">Daniel Edwards</a>.<sup id="cite_ref-1.5_manual_7-0" class="reference"><a href="#cite_note-1.5_manual-7">[7]</a></sup>
</p><p>During the 1980s and 1990s, a great effort was made to unify the work on new Lisp dialects (mostly successors to <a href="/wiki/Maclisp" title="Maclisp">Maclisp</a> such as <a href="/wiki/ZetaLisp" class="mw-redirect" title="ZetaLisp">ZetaLisp</a> and NIL (New Implementation of Lisp) into a single language. The new language, <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>, was somewhat compatible with the dialects it replaced (the book <i><a href="/wiki/Common_Lisp_the_Language" title="Common Lisp the Language">Common Lisp the Language</a></i> notes the compatibility of various constructs). In 1994, <a href="/wiki/ANSI" class="mw-redirect" title="ANSI">ANSI</a> published the Common Lisp standard, "ANSI X3.226-1994 Information Technology Programming Language Common Lisp".
</p>
<h3><span class="mw-headline" id="Timeline">Timeline</span></h3>
<table class="navbox">
<caption>Timeline of Lisp dialects<sup>(<a class="external text" href="/w/index.php?title=Template:Lisp&action=edit">edit</a>)</sup>
</caption>
<tbody><tr>
<th width="7%">1955
</th>
<th width="7%">1960
</th>
<th width="7%">1965
</th>
<th width="7%">1970
</th>
<th width="7%">1975
</th>
<th width="7%">1980
</th>
<th width="7%">1985
</th>
<th width="7%">1990
</th>
<th width="7%">1995
</th>
<th width="7%">2000
</th>
<th width="7%">2005
</th>
<th width="7%">2010
</th>
<th width="8%">2015
</th>
<th width="8%">2019
</th></tr>
<tr>
<th align="left" colspan="3" style="background:lightgray"> LISP 1, 1.5, <a href="/wiki/LISP_2" title="LISP 2">LISP 2<sup>(abandoned)</sup></a>
</th>
<td colspan="10">
</td></tr>
<tr>
<td colspan="2">
</td>
<th align="left" colspan="5" style="background:lightgray"> <a href="/wiki/Maclisp" title="Maclisp">Maclisp</a>
</th>
<td colspan="6">
</td></tr>
<tr>
<td colspan="3">
</td>
<th align="left" colspan="5" style="background:lightgray"> <a href="/wiki/Interlisp" title="Interlisp">Interlisp</a>
</th>
<td colspan="5">
</td></tr>
<tr>
<td colspan="4">
</td>
<th align="left" colspan="5" style="background:lightgray"> <a href="/wiki/Lisp_Machine_Lisp" title="Lisp Machine Lisp">Lisp Machine Lisp</a>
</th>
<td colspan="4">
</td></tr>
<tr>
<td colspan="4">
</td>
<th align="left" colspan="4" style="background:lightgray"> <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a>
</th>
<th align="left" colspan="2" style="background:lightgray"> R5RS
</th>
<th align="left" colspan="1" style="background:lightgray"> R6RS
</th>
<th align="left" colspan="3" style="background:lightgray"> R7RS small
</th></tr>
<tr>
<td colspan="4">
</td>
<th align="left" colspan="2" style="background:lightgray"> <a href="/wiki/NIL_(programming_language)" title="NIL (programming language)">NIL</a>
</th></tr>
<tr>
<td colspan="5">
</td>
<th align="left" colspan="2" style="background:lightgray"> <a href="/wiki/Franz_Lisp" title="Franz Lisp">Franz Lisp</a>
</th></tr>
<tr>
<td colspan="5">
</td>
<th align="left" colspan="9" style="background:lightgray"> <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>
</th></tr>
<tr>
<td colspan="5">
</td>
<th align="left" colspan="9" style="background:lightgray"> <a href="/wiki/Le_Lisp" title="Le Lisp">Le Lisp</a>
</th></tr>
<tr>
<td colspan="6">
</td>
<th align="left" colspan="3" style="background:lightgray"> <a href="/wiki/T_(programming_language)" title="T (programming language)">T</a>
</th>
<td colspan="4">
</td></tr>
<tr>
<td colspan="6">
</td>
<th align="left" colspan="8" style="background:lightgray"> <a href="/wiki/Emacs_Lisp" title="Emacs Lisp">Emacs Lisp</a>
</th></tr>
<tr>
<td colspan="6">
</td>
<th align="left" colspan="8" style="background:lightgray"> <a href="/wiki/AutoLISP" title="AutoLISP">AutoLISP</a>
</th></tr>
<tr>
<td colspan="6">
</td>
<th align="left" colspan="8" style="background:lightgray"> <a href="/wiki/PicoLisp" title="PicoLisp">PicoLisp</a>
</th></tr>
<tr>
<td colspan="7">
</td>
<th align="left" colspan="6" style="background:lightgray"> <a href="/wiki/EuLisp" title="EuLisp">EuLisp</a>
</th></tr>
<tr>
<td colspan="7">
</td>
<th align="left" colspan="8" style="background:lightgray"> <a href="/wiki/ISLISP" title="ISLISP">ISLISP</a>
</th></tr>
<tr>
<td colspan="7">
</td>
<th align="left" colspan="8" style="background:lightgray"> <a href="/wiki/OpenLisp" title="OpenLisp">OpenLisp</a>
</th></tr>
<tr>
<td colspan="7">
</td>
<th align="left" colspan="4" style="background:lightgray"> <a href="/wiki/PLT_Scheme" class="mw-redirect" title="PLT Scheme">PLT Scheme</a>
</th>
<th align="left" colspan="3" style="background:lightgray"> <a href="/wiki/Racket_(programming_language)" title="Racket (programming language)">Racket</a>
</th></tr>
<tr>
<td colspan="7">
</td>
<th align="left" colspan="7" style="background:lightgray"> <a href="/wiki/GNU_Guile" title="GNU Guile">GNU Guile</a>
</th></tr>
<tr>
<td colspan="9">
</td>
<th align="left" colspan="5" style="background:lightgray"> <a href="/wiki/AutoLISP" title="AutoLISP">Visual LISP</a>
</th></tr>
<tr>
<td colspan="10">
</td>
<th align="left" colspan="2" style="background:lightgray"> Qi, QiII
</th>
<th align="left" colspan="2" style="background:lightgray"> Shen
</th></tr>
<tr>
<td colspan="10">
</td>
<th align="left" colspan="4" style="background:lightgray"> <a href="/wiki/Clojure" title="Clojure">Clojure</a>
</th></tr>
<tr>
<td colspan="10">
</td>
<th align="left" colspan="4" style="background:lightgray"> <a href="/wiki/Arc_(programming_language)" title="Arc (programming language)">Arc</a>
</th></tr>
<tr>
<td colspan="10">
</td>
<th align="left" colspan="4" style="background:lightgray"> <a href="/wiki/LFE_(programming_language)" title="LFE (programming language)">LFE</a>
</th></tr>
<tr>
<td colspan="11">
</td>
<th align="left" colspan="3" style="background:lightgray"> <a href="/wiki/Hy" title="Hy">Hy</a>
</th></tr>
</tbody></table>
<h3><span class="mw-headline" id="Connection_to_artificial_intelligence">Connection to artificial intelligence</span></h3>
<p>Since inception, Lisp was closely connected with the <a href="/wiki/Artificial_intelligence" title="Artificial intelligence">artificial intelligence</a> research community, especially on <a href="/wiki/PDP-10" title="PDP-10">PDP-10</a><sup id="cite_ref-8" class="reference"><a href="#cite_note-8">[8]</a></sup> systems. Lisp was used as the implementation of the programming language <a href="/wiki/Planner_programming_language" class="mw-redirect" title="Planner programming language">Micro Planner</a>, which was used in the famous AI system <a href="/wiki/SHRDLU" title="SHRDLU">SHRDLU</a>. In the 1970s, as AI research spawned commercial offshoots, the performance of existing Lisp systems became a growing issue.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (March 2010)">citation needed</span></a></i>]</sup>
</p>
<h3><span class="mw-headline" id="Genealogy_and_variants">Genealogy and variants</span></h3>
<p>Over its sixty-year history, Lisp has spawned many variations on the core theme of an S-expression language. Moreover, each given dialect may have several implementations—for instance, there are more than a dozen implementations of <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>.
</p><p>Differences between dialects may be quite visible—for instance, Common Lisp uses the keyword <code>defun</code> to name a function, but Scheme uses <code>define</code>.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9">[9]</a></sup> Within a dialect that is standardized, however, conforming implementations support the same core language, but with different extensions and libraries.
</p>
<h4><span class="mw-headline" id="Historically_significant_dialects">Historically significant dialects</span></h4>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/wiki/File:LISP_machine.jpg" class="image"><img alt="" src="/media/wikipedia/commons/thumb/1/16/LISP_machine.jpg/220px-LISP_machine.jpg" decoding="async" width="220" height="291" class="thumbimage" data-file-width="1536" data-file-height="2032" /></a> <div class="thumbcaption"><div class="magnify"><a href="/wiki/File:LISP_machine.jpg" class="internal" title="Enlarge"></a></div>A <a href="/wiki/Lisp_machine" title="Lisp machine">Lisp machine</a> in the <a href="/wiki/MIT_Museum" title="MIT Museum">MIT Museum</a></div></div></div>
<div class="thumb tright"><div class="thumbinner" style="width:222px;"><a href="/wiki/File:4.3_BSD_UWisc_VAX_Emulation_Lisp_Manual.png" class="image"><img alt="" src="/media/wikipedia/commons/thumb/f/f7/4.3_BSD_UWisc_VAX_Emulation_Lisp_Manual.png/220px-4.3_BSD_UWisc_VAX_Emulation_Lisp_Manual.png" decoding="async" width="220" height="140" class="thumbimage" data-file-width="652" data-file-height="416" /></a> <div class="thumbcaption"><div class="magnify"><a href="/wiki/File:4.3_BSD_UWisc_VAX_Emulation_Lisp_Manual.png" class="internal" title="Enlarge"></a></div><a href="/wiki/4.3BSD" class="mw-redirect" title="4.3BSD">4.3 BSD</a> from the <a href="/wiki/University_of_Wisconsin" class="mw-redirect" title="University of Wisconsin">University of Wisconsin</a>, displaying the <a href="/wiki/Man_page" title="Man page">man page</a> for <a href="/wiki/Franz_Lisp" title="Franz Lisp">Franz Lisp</a></div></div></div>
<ul><li>LISP 1<sup id="cite_ref-10" class="reference"><a href="#cite_note-10">[10]</a></sup> – First implementation.</li>
<li>LISP 1.5<sup id="cite_ref-1.5_manual_7-1" class="reference"><a href="#cite_note-1.5_manual-7">[7]</a></sup> – First widely distributed version, developed by McCarthy and others at MIT. So named because it contained several improvements on the original "LISP 1" interpreter, but was not a major restructuring as the planned <a href="/wiki/LISP_2" title="LISP 2">LISP 2</a> would be.</li>
<li><a href="/w/index.php?title=Stanford_LISP&action=edit&redlink=1" class="new" title="Stanford LISP (page does not exist)">Stanford LISP</a> 1.6<sup id="cite_ref-11" class="reference"><a href="#cite_note-11">[11]</a></sup> – This was a successor to LISP 1.5 developed at the <a href="/wiki/Stanford_AI_Lab" class="mw-redirect" title="Stanford AI Lab">Stanford AI Lab</a>, and widely distributed to <a href="/wiki/PDP-10" title="PDP-10">PDP-10</a> systems running the <a href="/wiki/TOPS-10" title="TOPS-10">TOPS-10</a> operating system. It was rendered obsolete by Maclisp and InterLisp.</li>
<li><a href="/wiki/Maclisp" title="Maclisp">MACLISP</a><sup id="cite_ref-12" class="reference"><a href="#cite_note-12">[12]</a></sup> – developed for MIT's <a href="/wiki/Project_MAC" class="mw-redirect" title="Project MAC">Project MAC</a>, MACLISP is a direct descendant of LISP 1.5. It ran on the PDP-10 and <a href="/wiki/Multics" title="Multics">Multics</a> systems. MACLISP would later come to be called Maclisp, and is often referred to as MacLisp. The "MAC" in MACLISP is related neither to Apple's <a href="/wiki/Macintosh" title="Macintosh">Macintosh</a> nor to <a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">McCarthy</a>.</li>
<li><a href="/wiki/Interlisp" title="Interlisp">Interlisp</a><sup id="cite_ref-13" class="reference"><a href="#cite_note-13">[13]</a></sup> – developed at <a href="/wiki/BBN_Technologies" title="BBN Technologies">BBN Technologies</a> for PDP-10 systems running the <a href="/wiki/TENEX_(operating_system)" title="TENEX (operating system)">TENEX operating system</a>, later adopted as a "West coast" Lisp for the Xerox Lisp machines as <a href="/w/index.php?title=InterLisp-D&action=edit&redlink=1" class="new" title="InterLisp-D (page does not exist)">InterLisp-D</a>. A small version called "InterLISP 65" was published for the <a href="/wiki/MOS_6502" class="mw-redirect" title="MOS 6502">6502</a>-based <a href="/wiki/Atari_8-bit_family" title="Atari 8-bit family">Atari 8-bit family</a> computer line. For quite some time, Maclisp and InterLisp were strong competitors.</li>
<li><a href="/wiki/Franz_Lisp" title="Franz Lisp">Franz Lisp</a> – originally a <a href="/wiki/University_of_California,_Berkeley" title="University of California, Berkeley">University of California, Berkeley</a> project; later developed by Franz Inc. The name is a humorous deformation of the name "<a href="/wiki/Franz_Liszt" title="Franz Liszt">Franz Liszt</a>", and does not refer to <a href="/wiki/Allegro_Common_Lisp" title="Allegro Common Lisp">Allegro Common Lisp</a>, the dialect of Common Lisp sold by Franz Inc., in more recent years.</li>
<li><a href="/w/index.php?title=XLISP&action=edit&redlink=1" class="new" title="XLISP (page does not exist)">XLISP</a>, which <a href="/wiki/AutoLISP" title="AutoLISP">AutoLISP</a> was based on.</li>
<li><a href="/w/index.php?title=Standard_Lisp&action=edit&redlink=1" class="new" title="Standard Lisp (page does not exist)">Standard Lisp</a> and <a href="/wiki/Portable_Standard_Lisp" title="Portable Standard Lisp">Portable Standard Lisp</a> were widely used and ported, especially with the Computer Algebra System REDUCE.</li>
<li><a href="/wiki/ZetaLisp" class="mw-redirect" title="ZetaLisp">ZetaLisp</a>, also termed Lisp Machine Lisp – used on the <a href="/wiki/Lisp_machine" title="Lisp machine">Lisp machines</a>, direct descendant of Maclisp. ZetaLisp had a big influence on Common Lisp.</li>
<li><a href="/wiki/LeLisp" class="mw-redirect" title="LeLisp">LeLisp</a> is a French Lisp dialect. One of the first <a href="/wiki/Graphical_user_interface_builder" title="Graphical user interface builder">Interface Builders</a> (called SOS Interface<sup id="cite_ref-14" class="reference"><a href="#cite_note-14">[14]</a></sup>) was written in LeLisp.</li>
<li><a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a> (1975).<sup id="cite_ref-15" class="reference"><a href="#cite_note-15">[15]</a></sup></li>
<li><a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a> (1984), as described by <i><a href="/wiki/Common_Lisp_the_Language" title="Common Lisp the Language">Common Lisp the Language</a></i> – a consolidation of several divergent attempts (ZetaLisp, <a href="/wiki/Spice_Lisp" title="Spice Lisp">Spice Lisp</a>, <a href="/wiki/NIL_(programming_language)" title="NIL (programming language)">NIL</a>, and <a href="/wiki/S-1_Lisp" title="S-1 Lisp">S-1 Lisp</a>) to create successor dialects<sup id="cite_ref-16" class="reference"><a href="#cite_note-16">[16]</a></sup> to Maclisp, with substantive influences from the Scheme dialect as well. This version of Common Lisp was available for wide-ranging platforms and was accepted by many as a <a href="/wiki/De_facto_standard" title="De facto standard">de facto standard</a><sup id="cite_ref-17" class="reference"><a href="#cite_note-17">[17]</a></sup> until the publication of ANSI Common Lisp (ANSI X3.226-1994). Among the most widespread sub-dialects of Common Lisp are <a href="/wiki/Steel_Bank_Common_Lisp" title="Steel Bank Common Lisp">Steel Bank Common Lisp</a> (SBCL), CMU Common Lisp (CMU-CL), Clozure OpenMCL (not to be confused with Clojure!), GNU CLisp, and later versions of Franz Lisp; all of them adhere to the later ANSI CL standard (see below).</li>
<li><a href="/wiki/Dylan_(programming_language)" title="Dylan (programming language)">Dylan</a> was in its first version a mix of Scheme with the Common Lisp Object System.</li>
<li><a href="/wiki/EuLisp" title="EuLisp">EuLisp</a> – attempt to develop a new efficient and cleaned-up Lisp.</li>
<li><a href="/wiki/ISLISP" title="ISLISP">ISLISP</a> – attempt to develop a new efficient and cleaned-up Lisp. Standardized as ISO/IEC 13816:1997<sup id="cite_ref-18" class="reference"><a href="#cite_note-18">[18]</a></sup> and later revised as ISO/IEC 13816:2007:<sup id="cite_ref-19" class="reference"><a href="#cite_note-19">[19]</a></sup> <i>Information technology – Programming languages, their environments and system software interfaces – Programming language ISLISP</i>.</li>
<li>IEEE <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a> – IEEE standard, 1178–1990 (R1995)</li>
<li>ANSI <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a> – an <a href="/wiki/American_National_Standards_Institute" title="American National Standards Institute">American National Standards Institute</a> (ANSI) <a href="/wiki/Standardization" title="Standardization">standard</a> for Common Lisp, created by subcommittee <a href="/wiki/X3J13" title="X3J13">X3J13</a>, chartered<sup id="cite_ref-20" class="reference"><a href="#cite_note-20">[20]</a></sup> to begin with <i>Common Lisp: The Language</i> as a base document and to work through a public <a href="/wiki/Consensus_decision-making" title="Consensus decision-making">consensus</a> process to find solutions to shared issues of <a href="/wiki/Portability_(software)" class="mw-redirect" title="Portability (software)">portability</a> of programs and <a href="/wiki/Computer_compatibility" title="Computer compatibility">compatibility</a> of Common Lisp implementations. Although formally an ANSI standard, the implementation, sale, use, and influence of ANSI Common Lisp has been and continues to be seen worldwide.</li>
<li><a href="/wiki/ACL2" title="ACL2">ACL2</a> or "A Computational Logic for Applicative Common Lisp", an applicative (side-effect free) variant of Common LISP. ACL2 is both a programming language which can model computer systems, and a tool to help proving properties of those models.</li>
<li><a href="/wiki/Clojure" title="Clojure">Clojure</a>, a recent dialect of Lisp which compiles to the <a href="/wiki/Java_virtual_machine" title="Java virtual machine">Java virtual machine</a> and has a particular focus on <a href="/wiki/Concurrency_(computer_science)" title="Concurrency (computer science)">concurrency</a>.</li>
<li><a href="/wiki/Game_Oriented_Assembly_Lisp" title="Game Oriented Assembly Lisp">Game Oriented Assembly Lisp</a> (or GOAL) is a video game programming language developed by Andy Gavin and the <a href="/wiki/Jak_and_Daxter" title="Jak and Daxter">Jak and Daxter</a> team at <a href="/wiki/Naughty_Dog" title="Naughty Dog">Naughty Dog</a>. It was written using Allegro Common Lisp and used in the development of the entire <a href="/wiki/Jak_and_Daxter" title="Jak and Daxter">Jak and Daxter series of games</a>.</li></ul>
<h3><span class="mw-headline" id="2000_to_present">2000 to present</span></h3>
<p>After having declined somewhat in the 1990s, Lisp has experienced a resurgence of interest after 2000. Most new activity has been focused around implementations of <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>, <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a>, <a href="/wiki/Emacs_Lisp" title="Emacs Lisp">Emacs Lisp</a>, <a href="/wiki/Clojure" title="Clojure">Clojure</a>, and <a href="/wiki/Racket_(programming_language)" title="Racket (programming language)">Racket</a>, and includes development of new portable libraries and applications.
</p><p>Many new Lisp programmers were inspired by writers such as <a href="/wiki/Paul_Graham_(computer_programmer)" class="mw-redirect" title="Paul Graham (computer programmer)">Paul Graham</a> and <a href="/wiki/Eric_S._Raymond" title="Eric S. Raymond">Eric S. Raymond</a> to pursue a language others considered antiquated. New Lisp programmers often describe the language as an eye-opening experience and claim to be substantially more productive than in other languages.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21">[21]</a></sup> This increase in awareness may be contrasted to the "<a href="/wiki/AI_winter" title="AI winter">AI winter</a>" and Lisp's brief gain in the mid-1990s.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22">[22]</a></sup>
</p><p>Dan Weinreb lists in his survey of Common Lisp implementations<sup id="cite_ref-23" class="reference"><a href="#cite_note-23">[23]</a></sup> eleven actively maintained Common Lisp implementations. Scieneer Common Lisp is a new commercial implementation forked from CMUCL with a first release in 2002.
</p><p>The <a href="/wiki/Open-source-software_movement" title="Open-source-software movement">open source</a> community has created new supporting infrastructure: <a href="/wiki/CLiki" title="CLiki">CLiki</a> is a wiki that collects Common Lisp related information, the <a href="/w/index.php?title=Common_Lisp_directory&action=edit&redlink=1" class="new" title="Common Lisp directory (page does not exist)">Common Lisp directory</a> lists resources, #lisp is a popular IRC channel and allows the sharing and commenting of code snippets (with support by <a href="/w/index.php?title=Lisppaste&action=edit&redlink=1" class="new" title="Lisppaste (page does not exist)">lisppaste</a>, an <a href="/wiki/IRC_bot" title="IRC bot">IRC bot</a> written in Lisp), <a href="/w/index.php?title=Planet_Lisp&action=edit&redlink=1" class="new" title="Planet Lisp (page does not exist)">Planet Lisp</a> collects the contents of various Lisp-related blogs, on <a href="/w/index.php?title=LispForum&action=edit&redlink=1" class="new" title="LispForum (page does not exist)">LispForum</a> users discuss Lisp topics, <a href="/w/index.php?title=Lispjobs&action=edit&redlink=1" class="new" title="Lispjobs (page does not exist)">Lispjobs</a> is a service for announcing job offers and there is a weekly news service, <i><a href="/w/index.php?title=Weekly_Lisp_News&action=edit&redlink=1" class="new" title="Weekly Lisp News (page does not exist)">Weekly Lisp News</a></i>. <i>Common-lisp.net</i> is a hosting site for open source Common Lisp projects. <a href="/wiki/Quicklisp" class="mw-redirect" title="Quicklisp">Quicklisp</a> is a library manager for Common Lisp.
</p><p>Fifty years of Lisp (1958–2008) was celebrated at LISP50@OOPSLA.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24">[24]</a></sup> There are regular local user meetings in Boston, Vancouver, and Hamburg. Other events include the European Common Lisp Meeting, the European Lisp Symposium and an International Lisp Conference.
</p><p>The Scheme community actively maintains <a href="/wiki/Scheme_(programming_language)#Implementations" title="Scheme (programming language)">over twenty implementations</a>. Several significant new implementations (Chicken, Gambit, Gauche, Ikarus, Larceny, Ypsilon) have been developed in the 2000s (decade). The Revised<sup>5</sup> Report on the Algorithmic Language Scheme<sup id="cite_ref-25" class="reference"><a href="#cite_note-25">[25]</a></sup> standard of Scheme was widely accepted in the Scheme community. The <a href="/wiki/Scheme_Requests_for_Implementation" title="Scheme Requests for Implementation">Scheme Requests for Implementation</a> process has created a lot of quasi standard libraries and extensions for Scheme. User communities of individual Scheme implementations continue to grow. A new language standardization process was started in 2003 and led to the R<sup>6</sup>RS Scheme standard in 2007. Academic use of Scheme for teaching computer science seems to have declined somewhat. Some universities are no longer using Scheme in their computer science introductory courses;<sup id="cite_ref-26" class="reference"><a href="#cite_note-26">[26]</a></sup><sup id="cite_ref-27" class="reference"><a href="#cite_note-27">[27]</a></sup> MIT now uses <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a> instead of Scheme for its undergraduate <a href="/wiki/Computer_science" title="Computer science">computer science</a> program and MITx massive open online course.<sup id="cite_ref-MITEECS-Python_28-0" class="reference"><a href="#cite_note-MITEECS-Python-28">[28]</a></sup><sup id="cite_ref-MITx-Phyton_29-0" class="reference"><a href="#cite_note-MITx-Phyton-29">[29]</a></sup>
</p><p>There are several new dialects of Lisp: <a href="/wiki/Arc_(programming_language)" title="Arc (programming language)">Arc</a>, <a href="/wiki/Hy" title="Hy">Hy</a>, <a href="/wiki/Nu_(programming_language)" title="Nu (programming language)">Nu</a>, <a href="/w/index.php?title=Liskell&action=edit&redlink=1" class="new" title="Liskell (page does not exist)">Liskell</a>, and <a href="/wiki/LFE_(programming_language)" title="LFE (programming language)">LFE</a> (Lisp Flavored Erlang). The parser for <a href="/wiki/Julia_(programming_language)" title="Julia (programming language)">Julia</a> is implemented in Femtolisp, a dialect of <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a> (Julia is inspired by Scheme, which in turn is a Lisp dialect).
</p><p>In October 2019, Paul Graham released <a rel="nofollow" class="external text" href="http://paulgraham.com/bel.html">a specification for Bel</a>, "a new dialect of Lisp."
</p>
<h2><span class="mw-headline" id="Major_dialects">Major dialects</span></h2>
<p><a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a> and <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a> represent two major streams of Lisp development. These languages embody significantly different design choices.
</p><p><a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a> is a successor to <a href="/wiki/Maclisp" title="Maclisp">Maclisp</a>. The primary influences were <a href="/wiki/Lisp_Machine_Lisp" title="Lisp Machine Lisp">Lisp Machine Lisp</a>, Maclisp, <a href="/wiki/NIL_(programming_language)" title="NIL (programming language)">NIL</a>, <a href="/wiki/S-1_Lisp" title="S-1 Lisp">S-1 Lisp</a>, <a href="/wiki/Spice_Lisp" title="Spice Lisp">Spice Lisp</a>, and Scheme.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30">[30]</a></sup> It has many of the features of Lisp Machine Lisp (a large Lisp dialect used to program <a href="/wiki/Lisp_Machine" class="mw-redirect" title="Lisp Machine">Lisp Machines</a>), but was designed to be efficiently implementable on any personal computer or workstation. Common Lisp is a general-purpose programming language and thus has a large language standard including many built-in data types, functions, macros and other language elements, and an object system (<a href="/wiki/Common_Lisp_Object_System" title="Common Lisp Object System">Common Lisp Object System</a>). Common Lisp also borrowed certain features from Scheme such as <a href="/wiki/Lexical_scoping" class="mw-redirect" title="Lexical scoping">lexical scoping</a> and <a href="/wiki/Lexical_closure" class="mw-redirect" title="Lexical closure">lexical closures</a>. Common Lisp implementations are available for targeting different platforms such as the <a href="/wiki/LLVM" title="LLVM">LLVM</a>,<sup id="cite_ref-31" class="reference"><a href="#cite_note-31">[31]</a></sup> the <a href="/wiki/Java_virtual_machine" title="Java virtual machine">Java virtual machine</a>,<sup id="cite_ref-32" class="reference"><a href="#cite_note-32">[32]</a></sup>
x86-64, PowerPC, Alpha, ARM, Motorola 68000, and MIPS,<sup id="cite_ref-33" class="reference"><a href="#cite_note-33">[33]</a></sup> and operating systems such as Windows, macOS, Linux, Solaris, FreeBSD, NetBSD, OpenBSD, Dragonfly BSD, and Heroku.<sup id="cite_ref-34" class="reference"><a href="#cite_note-34">[34]</a></sup>
</p><p>Scheme is a statically scoped and properly tail-recursive dialect of the Lisp programming language invented by <a href="/wiki/Guy_L._Steele,_Jr." class="mw-redirect" title="Guy L. Steele, Jr.">Guy L. Steele, Jr.</a> and <a href="/wiki/Gerald_Jay_Sussman" title="Gerald Jay Sussman">Gerald Jay Sussman</a>. It was designed to have exceptionally clear and simple semantics and few different ways to form expressions. Designed about a decade earlier than Common Lisp, <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a> is a more minimalist design. It has a much smaller set of standard features but with certain implementation features (such as <a href="/wiki/Tail-call_optimization" class="mw-redirect" title="Tail-call optimization">tail-call optimization</a> and full <a href="/wiki/Continuation" title="Continuation">continuations</a>) not specified in Common Lisp. A wide variety of programming paradigms, including imperative, functional, and message passing styles, find convenient expression in Scheme. Scheme continues to evolve with a series of standards (Revised<sup>n</sup> Report on the Algorithmic Language Scheme) and a series of <a href="/wiki/Scheme_Requests_for_Implementation" title="Scheme Requests for Implementation">Scheme Requests for Implementation</a>.
</p><p><a href="/wiki/Clojure" title="Clojure">Clojure</a> is a recent dialect of Lisp that targets mainly the <a href="/wiki/Java_virtual_machine" title="Java virtual machine">Java virtual machine</a>, and the <a href="/wiki/Common_Language_Runtime" title="Common Language Runtime">Common Language Runtime</a> (CLR), the <a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a> VM, the Ruby VM <a href="/wiki/YARV" title="YARV">YARV</a>, and compiling to <a href="/wiki/JavaScript" title="JavaScript">JavaScript</a>. It is designed to be a pragmatic general-purpose language. Clojure draws considerable influences from <a href="/wiki/Haskell_(programming_language)" title="Haskell (programming language)">Haskell</a> and places a very strong emphasis on immutability.<sup id="cite_ref-clojure-immutability_35-0" class="reference"><a href="#cite_note-clojure-immutability-35">[35]</a></sup> Clojure provides access to Java frameworks and libraries, with optional type hints and <a href="/wiki/Type_inference" title="Type inference">type inference</a>, so that calls to Java can avoid reflection and enable fast primitive operations. Clojure is not designed to be backwards compatible with other Lisp dialects.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36">[36]</a></sup>
</p><p>Further, Lisp dialects are used as <a href="/wiki/Scripting_language" title="Scripting language">scripting languages</a> in many applications, with the best-known being <a href="/wiki/Emacs_Lisp" title="Emacs Lisp">Emacs Lisp</a> in the <a href="/wiki/Emacs" title="Emacs">Emacs</a> editor, <a href="/wiki/AutoLISP" title="AutoLISP">AutoLISP</a> and later <a href="/wiki/Visual_Lisp" class="mw-redirect" title="Visual Lisp">Visual Lisp</a> in <a href="/wiki/AutoCAD" title="AutoCAD">AutoCAD</a>, Nyquist in <a href="/wiki/Audacity_(audio_editor)" title="Audacity (audio editor)">Audacity</a>, Scheme in <a href="/wiki/LilyPond" title="LilyPond">LilyPond</a>. The potential small size of a useful Scheme interpreter makes it particularly popular for embedded scripting. Examples include <a href="/wiki/SIOD" title="SIOD">SIOD</a> and <a href="/wiki/TinyScheme" title="TinyScheme">TinyScheme</a>, both of which have been successfully embedded in the <a href="/wiki/GIMP" title="GIMP">GIMP</a> image processor under the generic name "Script-fu".<sup id="cite_ref-script-fu_37-0" class="reference"><a href="#cite_note-script-fu-37">[37]</a></sup> LIBREP, a Lisp interpreter by John Harper originally based on the <a href="/wiki/Emacs_Lisp" title="Emacs Lisp">Emacs Lisp</a> language, has been embedded in the <a href="/wiki/Sawfish_(window_manager)" title="Sawfish (window manager)">Sawfish</a> <a href="/wiki/Window_manager" title="Window manager">window manager</a>.<sup id="cite_ref-librep_38-0" class="reference"><a href="#cite_note-librep-38">[38]</a></sup>
</p>
<h3><span class="mw-headline" id="Standardized_dialects">Standardized dialects</span></h3>
<p>Lisp has officially standardized dialects: <a href="/wiki/Scheme_(programming_language)#R6RS" title="Scheme (programming language)">R6RS Scheme</a>, <a href="/wiki/Scheme_(programming_language)#R7RS" title="Scheme (programming language)">R7RS Scheme</a>, IEEE Scheme,<sup id="cite_ref-39" class="reference"><a href="#cite_note-39">[39]</a></sup> <a href="/wiki/ANSI_Common_Lisp" class="mw-redirect" title="ANSI Common Lisp">ANSI Common Lisp</a> and ISO <a href="/wiki/ISLISP" title="ISLISP">ISLISP</a>.
</p>
<h2><span class="mw-headline" id="Language_innovations">Language innovations</span></h2>
<p>Lisp was the first language where the structure of program code is represented faithfully and directly in a standard data structure—a quality much later dubbed "<a href="/wiki/Homoiconicity" title="Homoiconicity">homoiconicity</a>". Thus, Lisp functions can be manipulated, altered or even created within a Lisp program without lower-level manipulations. This is generally considered one of the main advantages of the language with regard to its expressive power, and makes the language suitable for syntactic macros and <a href="/wiki/Metacircular_evaluation" class="mw-redirect" title="Metacircular evaluation">metacircular evaluation</a>.
</p><p>A conditional using an <i><a href="/wiki/If%E2%80%93then%E2%80%93else" class="mw-redirect" title="If–then–else">if–then–else</a></i> syntax was invented by McCarthy in a Fortran context. He proposed its inclusion in <a href="/wiki/ALGOL" title="ALGOL">ALGOL</a>, but it was not made part of the <a href="/wiki/Algol_58" class="mw-redirect" title="Algol 58">Algol 58</a> specification. For Lisp, McCarthy used the more general <i>cond</i>-structure.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40">[40]</a></sup> <a href="/wiki/Algol_60" class="mw-redirect" title="Algol 60">Algol 60</a> took up <i>if–then–else</i> and popularized it.
</p><p>Lisp deeply influenced <a href="/wiki/Alan_Kay" title="Alan Kay">Alan Kay</a>, the leader of the research team that developed <a href="/wiki/Smalltalk" title="Smalltalk">Smalltalk</a> at <a href="/wiki/Xerox_PARC" class="mw-redirect" title="Xerox PARC">Xerox PARC</a>; and in turn Lisp was influenced by Smalltalk, with later dialects adopting object-oriented programming features (inheritance classes, encapsulating instances, message passing, etc.) in the 1970s. The <a href="/wiki/Flavors_(programming_language)" title="Flavors (programming language)">Flavors</a> object system introduced the concept of <a href="/wiki/Multiple_inheritance" title="Multiple inheritance">multiple inheritance</a> and the <a href="/wiki/Mixin" title="Mixin">mixin</a>. The <a href="/wiki/Common_Lisp_Object_System" title="Common Lisp Object System">Common Lisp Object System</a> provides multiple inheritance, multimethods with <a href="/wiki/Multiple_dispatch" title="Multiple dispatch">multiple dispatch</a>, and first-class <a href="/wiki/Generic_functions" class="mw-redirect" title="Generic functions">generic functions</a>, yielding a flexible and powerful form of <a href="/wiki/Dynamic_dispatch" title="Dynamic dispatch">dynamic dispatch</a>. It has served as the template for many subsequent Lisp (including <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a>) object systems, which are often implemented via a <a href="/wiki/Metaobject#Metaobject_Protocol" title="Metaobject">metaobject protocol</a>, a <a href="/wiki/Reflection_(computer_science)" class="mw-redirect" title="Reflection (computer science)">reflective</a> <a href="/wiki/Metacircular_evaluator" class="mw-redirect" title="Metacircular evaluator">metacircular design</a> in which the object system is defined in terms of itself: Lisp was only the second language after Smalltalk (and is still one of the very few languages) to possess such a metaobject system. Many years later, Alan Kay suggested that as a result of the confluence of these features, only Smalltalk and Lisp could be regarded as properly conceived object-oriented programming systems.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41">[41]</a></sup>
</p><p>Lisp introduced the concept of <a href="/wiki/Garbage_collection_(computer_science)" title="Garbage collection (computer science)">automatic garbage collection</a>, in which the system walks the <a href="/wiki/Heap_(memory_management)" class="mw-redirect" title="Heap (memory management)">heap</a> looking for unused memory. Progress in modern sophisticated garbage collection algorithms such as generational garbage collection was stimulated by its use in Lisp.<sup id="cite_ref-42" class="reference"><a href="#cite_note-42">[42]</a></sup>
</p><p><a href="/wiki/Edsger_W._Dijkstra" title="Edsger W. Dijkstra">Edsger W. Dijkstra</a> in his 1972 <a href="/wiki/Turing_Award" title="Turing Award">Turing Award</a> lecture said,
</p>
<dl><dd>"With a few very basic principles at its foundation, it [LISP] has shown a remarkable stability. Besides that, LISP has been the carrier for a considerable number of in a sense our most sophisticated computer applications. LISP has jokingly been described as “the most intelligent way to misuse a computer”. I think that description a great compliment because it transmits the full flavour of liberation: it has assisted a number of our most gifted fellow humans in thinking previously impossible thoughts."<sup id="cite_ref-43" class="reference"><a href="#cite_note-43">[43]</a></sup></dd></dl>
<p>Largely because of its resource requirements with respect to early computing hardware (including early microprocessors), Lisp did not become as popular outside of the <a href="/wiki/AI" class="mw-redirect" title="AI">AI</a> community as <a href="/wiki/Fortran" title="Fortran">Fortran</a> and the <a href="/wiki/ALGOL" title="ALGOL">ALGOL</a>-descended <a href="/wiki/C_(programming_language)" title="C (programming language)">C</a> language. Because of its suitability to complex and dynamic applications, Lisp is enjoying some resurgence of popular interest in the 2010s.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44">[44]</a></sup>
</p>
<h2><span class="mw-headline" id="Syntax_and_semantics">Syntax and semantics</span></h2>
<dl><dd><i><b>Note</b>: This article's examples are written in <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a> (though most are also valid in <a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a>).</i></dd></dl>
<h3><span id="Symbolic_expressions_.28S-expressions.29"></span><span class="mw-headline" id="Symbolic_expressions_(S-expressions)">Symbolic expressions (S-expressions)</span></h3>
<p>Lisp is an <a href="/wiki/Expression_oriented_language" class="mw-redirect" title="Expression oriented language">expression oriented language</a>. Unlike most other languages, no distinction is made between "expressions" and <a href="/wiki/Statement_(programming)" class="mw-redirect" title="Statement (programming)">"statements"</a>;<sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Accuracy_dispute#Disputed_statement" title="Wikipedia:Accuracy dispute"><span title="The material near this tag is possibly inaccurate or nonfactual. (April 2013)">dubious</span></a> <span class="metadata"> – <a href="/wiki/Talk:Lisp_(programming_language)#Dubious" title="Talk:Lisp (programming language)">discuss</a></span></i>]</sup> all code and data are written as expressions. When an expression is <i>evaluated</i>, it produces a value (in Common Lisp, possibly multiple values), which can then be embedded into other expressions. Each value can be any data type.
</p><p>McCarthy's 1958 paper introduced two types of syntax: <i>Symbolic expressions</i> (<a href="/wiki/S-expression" title="S-expression">S-expressions</a>, sexps), which mirror the internal representation of code and data; and <i>Meta expressions</i> (<a href="/wiki/M-expression" title="M-expression">M-expressions</a>), which express functions of S-expressions. M-expressions never found favor, and almost all Lisps today use S-expressions to manipulate both code and data.
</p><p>The use of parentheses is Lisp's most immediately obvious difference from other programming language families. As a result, students have long given Lisp nicknames such as <i>Lost In Stupid Parentheses</i>, or <i>Lots of Irritating Superfluous Parentheses</i>.<sup id="cite_ref-LEVIN2_45-0" class="reference"><a href="#cite_note-LEVIN2-45">[45]</a></sup> However, the S-expression syntax is also responsible for much of Lisp's power: the syntax is extremely regular, which facilitates manipulation by computer. However, the syntax of Lisp is not limited to traditional parentheses notation. It can be extended to include alternative notations. For example, XMLisp is a Common Lisp extension that employs the <a href="/wiki/Metaobject#Metaobject_protocol" title="Metaobject">metaobject protocol</a> to integrate S-expressions with the Extensible Markup Language (<a href="/wiki/XML" title="XML">XML</a>).
</p><p>The reliance on expressions gives the language great flexibility. Because Lisp <a href="/wiki/Function_(programming)" class="mw-redirect" title="Function (programming)">functions</a> are written as lists, they can be processed exactly like data. This allows easy writing of programs which manipulate other programs (<a href="/wiki/Metaprogramming" title="Metaprogramming">metaprogramming</a>). Many Lisp dialects exploit this feature using macro systems, which enables extension of the language almost without limit.
</p>
<h3><span class="mw-headline" id="Lists">Lists</span></h3>
<p>A Lisp list is written with its elements separated by <a href="/wiki/Whitespace_character" title="Whitespace character">whitespace</a>, and surrounded by parentheses. For example, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="nv">foo</span><span class="p">)</span></code> is a list whose elements are the three <i>atoms</i> <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">1</span></code>, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">2</span></code>, and <a href="/wiki/Foo" class="mw-redirect" title="Foo"><code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code></a>. These values are implicitly typed: they are respectively two integers and a Lisp-specific data type called a "symbol", and do not have to be declared as such.
</p><p>The empty list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">()</span></code> is also represented as the special atom <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="no">nil</span></code>. This is the only entity in Lisp which is both an atom and a list.
</p><p>Expressions are written as lists, using <a href="/wiki/Polish_notation" title="Polish notation">prefix notation</a>. The first element in the list is the name of a function, the name of a macro, a lambda expression or the name of a "special operator" (see below). The remainder of the list are the arguments. For example, the function <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">list</span></code> returns its arguments as a list, so the expression
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">list</span> <span class="mi">1</span> <span class="mi">2</span> <span class="p">(</span><span class="k">quote</span> <span class="nv">foo</span><span class="p">))</span>
</pre></div>
<p>evaluates to the list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="nv">foo</span><span class="p">)</span></code>. The "quote" before the <a href="/wiki/Foo" class="mw-redirect" title="Foo"><code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code></a> in the preceding example is a "special operator" which returns its argument without evaluating it. Any unquoted expressions are recursively evaluated before the enclosing expression is evaluated. For example,
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">list</span> <span class="mi">1</span> <span class="mi">2</span> <span class="p">(</span><span class="nb">list</span> <span class="mi">3</span> <span class="mi">4</span><span class="p">))</span>
</pre></div>
<p>evaluates to the list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="p">(</span><span class="mi">3</span> <span class="mi">4</span><span class="p">))</span></code>. Note that the third argument is a list; lists can be nested.
</p>
<h3><span class="mw-headline" id="Operators">Operators</span></h3>
<p>Arithmetic operators are treated similarly. The expression
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">+</span> <span class="mi">1</span> <span class="mi">2</span> <span class="mi">3</span> <span class="mi">4</span><span class="p">)</span>
</pre></div>
<p>evaluates to 10. The equivalent under <a href="/wiki/Infix_notation" title="Infix notation">infix notation</a> would be "<code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">1</span> <span class="nb">+</span> <span class="mi">2</span> <span class="nb">+</span> <span class="mi">3</span> <span class="nb">+</span> <span class="mi">4</span></code>".
</p><p>Lisp has no notion of operators as implemented in Algol-derived languages. Arithmetic operators in Lisp are <a href="/wiki/Variadic_function" title="Variadic function">variadic functions</a> (or <i>n-ary</i>), able to take any number of arguments. A C-style '++' increment operator is sometimes implemented under the name <tt>incf</tt> giving syntax
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">incf</span> <span class="nv">x</span><span class="p">)</span>
</pre></div>
<p>equivalent to <tt>(setq x (+ x 1))</tt>, returning the new value of <tt>x</tt>.
</p><p>"Special operators" (sometimes called "special forms") provide Lisp's control structure. For example, the special operator <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">if</span></code> takes three arguments. If the first argument is non-nil, it evaluates to the second argument; otherwise, it evaluates to the third argument. Thus, the expression
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="k">if</span> <span class="no">nil</span>
<span class="p">(</span><span class="nb">list</span> <span class="mi">1</span> <span class="mi">2</span> <span class="s">"foo"</span><span class="p">)</span>
<span class="p">(</span><span class="nb">list</span> <span class="mi">3</span> <span class="mi">4</span> <span class="s">"bar"</span><span class="p">))</span>
</pre></div>
<p>evaluates to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">3</span> <span class="mi">4</span> <span class="s">"bar"</span><span class="p">)</span></code>. Of course, this would be more useful if a non-trivial expression had been substituted in place of <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="no">nil</span></code>.
</p><p>Lisp also provides logical operators <b>and</b>, <b>or</b> and <b>not</b>. The <b>and</b> and <b>or</b> operators do <a href="/wiki/Short_circuit_evaluation" class="mw-redirect" title="Short circuit evaluation">short circuit evaluation</a> and will return their first nil and non-nil argument respectively.
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">or</span> <span class="p">(</span><span class="nb">and</span> <span class="s">"zero"</span> <span class="no">nil</span> <span class="s">"never"</span><span class="p">)</span> <span class="s">"James"</span> <span class="ss">'task</span> <span class="ss">'time</span><span class="p">)</span>
</pre></div>
<p>will evaluate to "James".
</p>
<h3><span class="mw-headline" id="Lambda_expressions_and_function_definition">Lambda expressions and function definition</span></h3>
<p>Another special operator, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">lambda</span></code>, is used to bind variables to values which are then evaluated within an expression. This operator is also used to create functions: the arguments to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">lambda</span></code> are a list of arguments, and the expression or expressions to which the function evaluates (the returned value is the value of the last expression that is evaluated). The expression
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="k">lambda</span> <span class="p">(</span><span class="nv">arg</span><span class="p">)</span> <span class="p">(</span><span class="nb">+</span> <span class="nv">arg</span> <span class="mi">1</span><span class="p">))</span>
</pre></div>
<p>evaluates to a function that, when applied, takes one argument, binds it to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">arg</span></code> and returns the number one greater than that argument. Lambda expressions are treated no differently from named functions; they are invoked the same way. Therefore, the expression
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">((</span><span class="k">lambda</span> <span class="p">(</span><span class="nv">arg</span><span class="p">)</span> <span class="p">(</span><span class="nb">+</span> <span class="nv">arg</span> <span class="mi">1</span><span class="p">))</span> <span class="mi">5</span><span class="p">)</span>
</pre></div>
<p>evaluates to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">6</span></code>. Here, we're doing a function application: we execute the <a href="/wiki/Anonymous_function" title="Anonymous function">anonymous function</a> by passing to it the value 5.
</p><p>Named functions are created by storing a lambda expression in a symbol using the <a href="/wiki/Defun" title="Defun">defun</a> macro.
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">defun</span> <span class="nv">foo</span> <span class="p">(</span><span class="nv">a</span> <span class="nv">b</span> <span class="nv">c</span> <span class="nv">d</span><span class="p">)</span> <span class="p">(</span><span class="nb">+</span> <span class="nv">a</span> <span class="nv">b</span> <span class="nv">c</span> <span class="nv">d</span><span class="p">))</span>
</pre></div>
<p><code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nb">defun</span> <span class="nv">f</span> <span class="p">(</span><span class="nv">a</span><span class="p">)</span> <span class="nv">b...</span><span class="p">)</span></code> defines a new function named <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">f</span></code> in the global environment. It is conceptually similar to the expression:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">setf</span> <span class="p">(</span><span class="nb">fdefinition</span> <span class="ss">'f</span><span class="p">)</span> <span class="nf">#'</span><span class="p">(</span><span class="k">lambda</span> <span class="p">(</span><span class="nv">a</span><span class="p">)</span> <span class="p">(</span><span class="k">block</span> <span class="nv">f</span> <span class="nv">b...</span><span class="p">)))</span>
</pre></div>
<h3><span class="mw-headline" id="Atoms">Atoms</span></h3>
<p>In the original <b>LISP</b> there were two fundamental <a href="/wiki/Data_type" title="Data type">data types</a>: atoms and lists. A list was a finite ordered sequence of elements, where each element is either an atom or a list, and an atom was a <a href="/wiki/Number" title="Number">number</a> or a symbol. A symbol was essentially a unique named item, written as an <a href="/wiki/Alphanumeric" title="Alphanumeric">alphanumeric</a> string in <a href="/wiki/Source_code" title="Source code">source code</a>, and used either as a variable name or as a data item in <a href="/wiki/Symbolic_processing" class="mw-redirect" title="Symbolic processing">symbolic processing</a>. For example, the list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">FOO</span> <span class="p">(</span><span class="nv">BAR</span> <span class="mi">1</span><span class="p">)</span> <span class="mi">2</span><span class="p">)</span></code> contains three elements: the symbol <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">FOO</span></code>, the list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">BAR</span> <span class="mi">1</span><span class="p">)</span></code>, and the number 2.
</p><p>The essential difference between atoms and lists was that atoms were immutable and unique. Two atoms that appeared in different places in source code but were written in exactly the same way represented the same object,<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2008)">citation needed</span></a></i>]</sup> whereas each list was a separate object that could be altered independently of other lists and could be distinguished from other lists by comparison operators.
</p><p>As more data types were introduced in later Lisp dialects, and <a href="/wiki/Programming_style" title="Programming style">programming styles</a> evolved, the concept of an atom lost importance.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2008)">citation needed</span></a></i>]</sup> Many dialects still retained the predicate <i>atom</i> for <a href="/wiki/Legacy_compatibility" class="mw-redirect" title="Legacy compatibility">legacy compatibility</a>,<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2008)">citation needed</span></a></i>]</sup> defining it true for any object which is not a cons.
</p>
<h3><span class="mw-headline" id="Conses_and_lists">Conses and lists</span></h3>
<div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Cons" title="Cons">Cons</a></div>
<div class="thumb tright"><div class="thumbinner" style="width:302px;"><a href="/wiki/File:Cons-cells.svg" class="image"><img alt="" src="/media/wikipedia/commons/thumb/1/1b/Cons-cells.svg/300px-Cons-cells.svg.png" decoding="async" width="300" height="73" class="thumbimage" srcset="/media/wikipedia/commons/thumb/1/1b/Cons-cells.svg/450px-Cons-cells.svg.png 1.5x, /media/wikipedia/commons/thumb/1/1b/Cons-cells.svg/600px-Cons-cells.svg.png 2x" data-file-width="685" data-file-height="167" /></a> <div class="thumbcaption"><div class="magnify"><a href="/wiki/File:Cons-cells.svg" class="internal" title="Enlarge"></a></div>Box-and-<a href="/wiki/Pointer_(computer_programming)" title="Pointer (computer programming)">pointer</a> diagram for the list (42 69 613)</div></div></div>
<p>A Lisp list is implemented as a <a href="/wiki/Singly_linked_list" class="mw-redirect" title="Singly linked list">singly linked list</a>.<sup id="cite_ref-SebestaLanguages_46-0" class="reference"><a href="#cite_note-SebestaLanguages-46">[46]</a></sup> Each cell of this list is called a <i>cons</i> (in Scheme, a <i>pair</i>), and is composed of two <a href="/wiki/Pointer_(computer_programming)" title="Pointer (computer programming)">pointers</a>, called the <i>car</i> and <i>cdr</i>. These are respectively equivalent to the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">data</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">next</span></code> fields discussed in the article <i><a href="/wiki/Linked_list" title="Linked list">linked list</a></i>.
</p><p>Of the many data structures that can be built out of cons cells, one of the most basic is called a <i>proper list</i>. A proper list is either the special <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="no">nil</span></code> (empty list) symbol, or a cons in which the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">car</span></code> points to a datum (which may be another cons structure, such as a list), and the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cdr</span></code> points to another proper list.
</p><p>If a given cons is taken to be the head of a linked list, then its car points to the first element of the list, and its cdr points to the rest of the list. For this reason, the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">car</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cdr</span></code> functions are also called <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">first</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">rest</span></code> when referring to conses which are part of a linked list (rather than, say, a tree).
</p><p>Thus, a Lisp list is not an atomic object, as an instance of a container class in C++ or Java would be. A list is nothing more than an aggregate of linked conses. A variable which refers to a given list is simply a pointer to the first cons in the list. Traversal of a list can be done by <i>cdring down</i> the list; that is, taking successive cdrs to visit each cons of the list; or by using any of several <a href="/wiki/Higher-order_function" title="Higher-order function">higher-order functions</a> to map a function over a list.
</p><p>Because conses and lists are so universal in Lisp systems, it is a common misconception that they are Lisp's only data structures. In fact, all but the most simplistic Lisps have other data structures, such as vectors (<a href="/wiki/Array_data_type" title="Array data type">arrays</a>), hash tables, structures, and so forth.
</p>
<h4><span class="mw-headline" id="S-expressions_represent_lists">S-expressions represent lists</span></h4>
<p>Parenthesized S-expressions represent linked list structures. There are several ways to represent the same list as an S-expression. A cons can be written in <i>dotted-pair notation</i> as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="o">.</span> <span class="nv">b</span><span class="p">)</span></code>, where <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">a</span></code> is the car and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">b</span></code> the cdr. A longer proper list might be written <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="o">.</span> <span class="p">(</span><span class="nv">b</span> <span class="o">.</span> <span class="p">(</span><span class="nv">c</span> <span class="o">.</span> <span class="p">(</span><span class="nv">d</span> <span class="o">.</span> <span class="no">nil</span><span class="p">))))</span></code> in dotted-pair notation. This is conventionally abbreviated as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="nv">b</span> <span class="nv">c</span> <span class="nv">d</span><span class="p">)</span></code> in <i>list notation</i>. An improper list<sup id="cite_ref-47" class="reference"><a href="#cite_note-47">[47]</a></sup> may be written in a combination of the two – as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="nv">b</span> <span class="nv">c</span> <span class="o">.</span> <span class="nv">d</span><span class="p">)</span></code> for the list of three conses whose last cdr is <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">d</span></code> (i.e., the list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="o">.</span> <span class="p">(</span><span class="nv">b</span> <span class="o">.</span> <span class="p">(</span><span class="nv">c</span> <span class="o">.</span> <span class="nv">d</span><span class="p">)))</span></code> in fully specified form).
</p>
<h4><span class="mw-headline" id="List-processing_procedures">List-processing procedures</span></h4>
<p>Lisp provides many built-in procedures for accessing and controlling lists. Lists can be created directly with the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">list</span></code> procedure, which takes any number of arguments, and returns the list of these arguments.
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">list</span> <span class="mi">1</span> <span class="mi">2</span> <span class="ss">'a</span> <span class="mi">3</span><span class="p">)</span>
<span class="c1">;Output: (1 2 a 3)</span>
</pre></div>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">list</span> <span class="mi">1</span> <span class="o">'</span><span class="p">(</span><span class="mi">2</span> <span class="mi">3</span><span class="p">)</span> <span class="mi">4</span><span class="p">)</span>
<span class="c1">;Output: (1 (2 3) 4)</span>
</pre></div>
<p>Because of the way that lists are constructed from <a href="/wiki/Cons_pair" class="mw-redirect" title="Cons pair">cons pairs</a>, the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cons</span></code> procedure can be used to add an element to the front of a list. Note that the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cons</span></code> procedure is asymmetric in how it handles list arguments, because of how lists are constructed.
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">cons</span> <span class="mi">1</span> <span class="o">'</span><span class="p">(</span><span class="mi">2</span> <span class="mi">3</span><span class="p">))</span>
<span class="c1">;Output: (1 2 3)</span>
</pre></div>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">cons</span> <span class="o">'</span><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span><span class="p">)</span> <span class="o">'</span><span class="p">(</span><span class="mi">3</span> <span class="mi">4</span><span class="p">))</span>
<span class="c1">;Output: ((1 2) 3 4)</span>
</pre></div>
<p>The <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">append</span></code> procedure appends two (or more) lists to one another. Because Lisp lists are linked lists, appending two lists has <a href="/wiki/Big_O_notation" title="Big O notation">asymptotic time complexity</a> <span class="mwe-math-element"><span class="mwe-math-mathml-inline mwe-math-mathml-a11y" style="display: none;"><math xmlns="http://www.w3.org/1998/Math/MathML" alttext="{\displaystyle O(n)}">
<semantics>
<mrow class="MJX-TeXAtom-ORD">
<mstyle displaystyle="true" scriptlevel="0">
<mi>O</mi>
<mo stretchy="false">(</mo>
<mi>n</mi>
<mo stretchy="false">)</mo>
</mstyle>
</mrow>
<annotation encoding="application/x-tex">{\displaystyle O(n)}</annotation>
</semantics>
</math></span><img src="/media/api/rest_v1/media/math/render/svg/34109fe397fdcff370079185bfdb65826cb5565a" class="mwe-math-fallback-image-inline" aria-hidden="true" style="vertical-align: -0.838ex; width:4.977ex; height:2.843ex;" alt="O(n)"/></span>
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">append</span> <span class="o">'</span><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span><span class="p">)</span> <span class="o">'</span><span class="p">(</span><span class="mi">3</span> <span class="mi">4</span><span class="p">))</span>
<span class="c1">;Output: (1 2 3 4)</span>
</pre></div>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">append</span> <span class="o">'</span><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="mi">3</span><span class="p">)</span> <span class="o">'</span><span class="p">()</span> <span class="o">'</span><span class="p">(</span><span class="nv">a</span><span class="p">)</span> <span class="o">'</span><span class="p">(</span><span class="mi">5</span> <span class="mi">6</span><span class="p">))</span>
<span class="c1">;Output: (1 2 3 a 5 6)</span>
</pre></div>
<h4><span class="mw-headline" id="Shared_structure">Shared structure</span></h4>
<p>Lisp lists, being simple linked lists, can share structure with one another. That is to say, two lists can have the same <i>tail</i>, or final sequence of conses. For instance, after the execution of the following Common Lisp code:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span><span class="p">(</span><span class="nb">setf</span> <span class="nv">foo</span> <span class="p">(</span><span class="nb">list</span> <span class="ss">'a</span> <span class="ss">'b</span> <span class="ss">'c</span><span class="p">))</span>
<span class="p">(</span><span class="nb">setf</span> <span class="nv">bar</span> <span class="p">(</span><span class="nb">cons</span> <span class="ss">'x</span> <span class="p">(</span><span class="nb">cdr</span> <span class="nv">foo</span><span class="p">)))</span>
</pre></div>
<p>the lists <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">bar</span></code> are <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="nv">b</span> <span class="nv">c</span><span class="p">)</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">x</span> <span class="nv">b</span> <span class="nv">c</span><span class="p">)</span></code> respectively. However, the tail <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">b</span> <span class="nv">c</span><span class="p">)</span></code> is the same structure in both lists. It is not a copy; the cons cells pointing to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">b</span></code> and <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">c</span></code> are in the same memory locations for both lists.
</p><p>Sharing structure rather than copying can give a dramatic performance improvement. However, this technique can interact in undesired ways with functions that alter lists passed to them as arguments. Altering one list, such as by replacing the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">c</span></code> with a <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">goose</span></code>, will affect the other:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">setf</span> <span class="p">(</span><span class="nb">third</span> <span class="nv">foo</span><span class="p">)</span> <span class="ss">'goose</span><span class="p">)</span>
</pre></div>
<p>This changes <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code> to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">a</span> <span class="nv">b</span> <span class="nv">goose</span><span class="p">)</span></code>, but thereby also changes <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">bar</span></code> to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">x</span> <span class="nv">b</span> <span class="nv">goose</span><span class="p">)</span></code> – a possibly unexpected result. This can be a source of bugs, and functions which alter their arguments are documented as <i>destructive</i> for this very reason.
</p><p>Aficionados of <a href="/wiki/Functional_programming" title="Functional programming">functional programming</a> avoid destructive functions. In the Scheme dialect, which favors the functional style, the names of destructive functions are marked with a cautionary exclamation point, or "bang"—such as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">set-car!</span></code> (read <i>set car bang</i>), which replaces the car of a cons. In the Common Lisp dialect, destructive functions are commonplace; the equivalent of <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">set-car!</span></code> is named <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">rplaca</span></code> for "replace car." This function is rarely seen however as Common Lisp includes a special facility, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">setf</span></code>, to make it easier to define and use destructive functions. A frequent style in Common Lisp is to write code functionally (without destructive calls) when prototyping, then to add destructive calls as an optimization where it is safe to do so.
</p>
<h3><span class="mw-headline" id="Self-evaluating_forms_and_quoting">Self-evaluating forms and quoting</span></h3>
<p>Lisp evaluates expressions which are entered by the user. Symbols and lists evaluate to some other (usually, simpler) expression – for instance, a symbol evaluates to the value of the variable it names; <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nb">+</span> <span class="mi">2</span> <span class="mi">3</span><span class="p">)</span></code> evaluates to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">5</span></code>. However, most other forms evaluate to themselves: if entering <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">5</span></code> into Lisp, it returns <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">5</span></code>.
</p><p>Any expression can also be marked to prevent it from being evaluated (as is necessary for symbols and lists). This is the role of the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">quote</span></code> special operator, or its abbreviation <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">'</span></code> (one quotation mark). For instance, usually if entering the symbol <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code>, it returns the value of the corresponding variable (or an error, if there is no such variable). To refer to the literal symbol, enter <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="k">quote</span> <span class="nv">foo</span><span class="p">)</span></code> or, usually, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="ss">'foo</span></code>.
</p><p><span id="Backquote"></span>Both Common Lisp and Scheme also support the <i>backquote</i> operator (termed <i><a href="/wiki/Quasiquote" class="mw-redirect" title="Quasiquote">quasiquote</a></i> in Scheme), entered with the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">`</span></code> character (<a href="/wiki/Grave_accent#Use_in_programming" title="Grave accent">grave accent</a>). This is almost the same as the plain quote, except it allows expressions to be evaluated and their values interpolated into a quoted list with the comma <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">,</span></code> <i>unquote</i> and comma-at <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">,@</span></code> <i>splice</i> operators. If the variable <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">snue</span></code> has the value <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">bar</span> <span class="nv">baz</span><span class="p">)</span></code> then <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">`</span><span class="p">(</span><span class="nv">foo</span> <span class="o">,</span><span class="nv">snue</span><span class="p">)</span></code> evaluates to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">foo</span> <span class="p">(</span><span class="nv">bar</span> <span class="nv">baz</span><span class="p">))</span></code>, while <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="o">`</span><span class="p">(</span><span class="nv">foo</span> <span class="o">,@</span><span class="nv">snue</span><span class="p">)</span></code> evaluates to <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nv">foo</span> <span class="nv">bar</span> <span class="nv">baz</span><span class="p">)</span></code>. The backquote is most often used in defining macro expansions.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48">[48]</a></sup><sup id="cite_ref-49" class="reference"><a href="#cite_note-49">[49]</a></sup>
</p><p>Self-evaluating forms and quoted forms are Lisp's equivalent of literals. It may be possible to modify the values of (mutable) literals in program code. For instance, if a function returns a quoted form, and the code that calls the function modifies the form, this may alter the behavior of the function on subsequent invocations.
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span><span class="p">(</span><span class="nb">defun</span> <span class="nv">should-be-constant</span> <span class="p">()</span>
<span class="o">'</span><span class="p">(</span><span class="nv">one</span> <span class="nv">two</span> <span class="nv">three</span><span class="p">))</span>
<span class="p">(</span><span class="k">let</span> <span class="p">((</span><span class="nv">stuff</span> <span class="p">(</span><span class="nv">should-be-constant</span><span class="p">)))</span>
<span class="p">(</span><span class="nb">setf</span> <span class="p">(</span><span class="nb">third</span> <span class="nv">stuff</span><span class="p">)</span> <span class="ss">'bizarre</span><span class="p">))</span> <span class="c1">; bad!</span>
<span class="p">(</span><span class="nv">should-be-constant</span><span class="p">)</span> <span class="c1">; returns (one two bizarre)</span>
</pre></div>
<p>Modifying a quoted form like this is generally considered bad style, and is defined by ANSI Common Lisp as erroneous (resulting in "undefined" behavior in compiled files, because the file-compiler can coalesce similar constants, put them in write-protected memory, etc.).
</p><p>Lisp's formalization of quotation has been noted by <a href="/wiki/Douglas_Hofstadter" title="Douglas Hofstadter">Douglas Hofstadter</a> (in <i><a href="/wiki/G%C3%B6del,_Escher,_Bach" title="Gödel, Escher, Bach">Gödel, Escher, Bach</a></i>) and others as an example of the <a href="/wiki/Philosophy" title="Philosophy">philosophical</a> idea of <a href="/wiki/Self-reference" title="Self-reference">self-reference</a>.
</p>
<h3><span class="mw-headline" id="Scope_and_closure">Scope and closure</span></h3>
<p>The Lisp family splits over the use of <a href="/wiki/Dynamic_scoping" class="mw-redirect" title="Dynamic scoping">dynamic</a> or <a href="/wiki/Static_scoping" class="mw-redirect" title="Static scoping">static</a> (a.k.a. lexical) <a href="/wiki/Scope_(programming)" class="mw-redirect" title="Scope (programming)">scope</a>. Clojure, Common Lisp and Scheme make use of static scoping by default, while <a href="/wiki/NewLISP" title="NewLISP">newLISP</a>, <a href="/wiki/Picolisp" class="mw-redirect" title="Picolisp">Picolisp</a> and the embedded languages in <a href="/wiki/Emacs" title="Emacs">Emacs</a> and <a href="/wiki/AutoCAD" title="AutoCAD">AutoCAD</a> use dynamic scoping. Since version 24.1, Emacs uses both dynamic and lexical scoping.
</p>
<h3><span id="List_structure_of_program_code.3B_exploitation_by_macros_and_compilers"></span><span class="mw-headline" id="List_structure_of_program_code;_exploitation_by_macros_and_compilers">List structure of program code; exploitation by macros and compilers</span></h3>
<p>A fundamental distinction between Lisp and other languages is that in Lisp, the textual representation of a program is simply a human-readable description of the same internal data structures (linked lists, symbols, number, characters, etc.) as would be used by the underlying Lisp system.
</p><p>Lisp uses this to implement a very powerful macro system. Like other macro languages such as <a href="/wiki/C_(programming_language)" title="C (programming language)">C</a>, a macro returns code that can then be compiled. However, unlike C macros, the macros are Lisp functions and so can exploit the full power of Lisp.
</p><p>Further, because Lisp code has the same structure as lists, macros can be built with any of the list-processing functions in the language. In short, anything that Lisp can do to a data structure, Lisp macros can do to code. In contrast, in most other languages, the parser's output is purely internal to the language implementation and cannot be manipulated by the programmer.
</p><p>This feature makes it easy to develop <i>efficient</i> languages within languages. For example, the Common Lisp Object System can be implemented cleanly as a language extension using macros. This means that if an application needs a different inheritance mechanism, it can use a different object system. This is in stark contrast to most other languages; for example, Java does not support multiple inheritance and there is no reasonable way to add it.
</p><p>In simplistic Lisp implementations, this list structure is directly <a href="/wiki/Interpreter_(computing)" title="Interpreter (computing)">interpreted</a> to run the program; a function is literally a piece of list structure which is traversed by the interpreter in executing it. However, most substantial Lisp systems also include a compiler. The compiler translates list structure into machine code or <a href="/wiki/Bytecode" title="Bytecode">bytecode</a> for execution. This code can run as fast as code compiled in conventional languages such as C.
</p><p>Macros expand before the compilation step, and thus offer some interesting options. If a program needs a precomputed table, then a macro might create the table at compile time, so the compiler need only output the table and need not call code to create the table at run time. Some Lisp implementations even have a mechanism, <code>eval-when</code>, that allows code to be present during compile time (when a macro would need it), but not present in the emitted module.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50">[50]</a></sup>
</p>
<h3><span id="Evaluation_and_the_read.E2.80.93eval.E2.80.93print_loop"></span><span class="mw-headline" id="Evaluation_and_the_read–eval–print_loop">Evaluation and the read–eval–print loop</span></h3>
<p>Lisp languages are often used with an interactive <a href="/wiki/Command_line" class="mw-redirect" title="Command line">command line</a>, which may be combined with an <a href="/wiki/Integrated_development_environment" title="Integrated development environment">integrated development environment</a> (IDE). The user types in expressions at the command line, or directs the IDE to transmit them to the Lisp system. Lisp <i>reads</i> the entered expressions, <i>evaluates</i> them, and <i>prints</i> the result. For this reason, the Lisp command line is called a <i><a href="/wiki/Read%E2%80%93eval%E2%80%93print_loop" title="Read–eval–print loop">read–eval–print loop</a></i> (<a href="/wiki/REPL" class="mw-redirect" title="REPL">REPL</a>).
</p><p>The basic operation of the REPL is as follows. This is a simplistic description which omits many elements of a real Lisp, such as quoting and macros.
</p><p>The <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">read</span></code> function accepts textual S-expressions as input, and parses them into an internal data structure. For instance, if you type the text <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nb">+</span> <span class="mi">1</span> <span class="mi">2</span><span class="p">)</span></code> at the prompt, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">read</span></code> translates this into a linked list with three elements: the symbol <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">+</span></code>, the number 1, and the number 2. It so happens that this list is also a valid piece of Lisp code; that is, it can be evaluated. This is because the car of the list names a function—the addition operation.
</p><p>Note that a <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code> will be read as a single symbol. <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">123</span></code> will be read as the number one hundred and twenty-three. <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="s">"123"</span></code> will be read as the string "123".
</p><p>The <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">eval</span></code> function evaluates the data, returning zero or more other Lisp data as a result. Evaluation does not have to mean interpretation; some Lisp systems compile every expression to native machine code. It is simple, however, to describe evaluation as interpretation: To evaluate a list whose car names a function, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">eval</span></code> first evaluates each of the arguments given in its cdr, then applies the function to the arguments. In this case, the function is addition, and applying it to the argument list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span><span class="p">)</span></code> yields the answer <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">3</span></code>. This is the result of the evaluation.
</p><p>The symbol <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">foo</span></code> evaluates to the value of the symbol foo. Data like the string "123" evaluates to the same string. The list <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="k">quote</span> <span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="mi">3</span><span class="p">))</span></code> evaluates to the list (1 2 3).
</p><p>It is the job of the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">print</span></code> function to represent output to the user. For a simple result such as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="mi">3</span></code> this is trivial. An expression which evaluated to a piece of list structure would require that <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">print</span></code> traverse the list and print it out as an S-expression.
</p><p>To implement a Lisp REPL, it is necessary only to implement these three functions and an infinite-loop function. (Naturally, the implementation of <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">eval</span></code> will be complex, since it must also implement all special operators like <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">if</span></code> or <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="k">lambda</span></code>.) This done, a basic REPL is one line of code: <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="nb">loop</span> <span class="p">(</span><span class="nb">print</span> <span class="p">(</span><span class="nb">eval</span> <span class="p">(</span><span class="nb">read</span><span class="p">))))</span></code>.
</p><p>The Lisp REPL typically also provides input editing, an input history, error handling and an interface to the debugger.
</p><p>Lisp is usually evaluated <a href="/wiki/Eager_evaluation" title="Eager evaluation">eagerly</a>. In <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>, arguments are evaluated in <a href="/wiki/Applicative_order" class="mw-redirect" title="Applicative order">applicative order</a> ('leftmost innermost'), while in <a href="/wiki/Scheme_programming_language" class="mw-redirect" title="Scheme programming language">Scheme</a> order of arguments is undefined, leaving room for optimization by a compiler.
</p>
<h3><span class="mw-headline" id="Control_structures">Control structures</span></h3>
<p>Lisp originally had very few control structures, but many more were added during the language's evolution. (Lisp's original conditional operator, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">cond</span></code>, is the precursor to later <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">if-then-else</span></code> structures.)
</p><p>Programmers in the Scheme dialect often express loops using <a href="/wiki/Tail_recursion" class="mw-redirect" title="Tail recursion">tail recursion</a>. Scheme's commonality in academic computer science has led some students to believe that tail recursion is the only, or the most common, way to write iterations in Lisp, but this is incorrect. All oft-seen Lisp dialects have imperative-style iteration constructs, from Scheme's <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">do</span></code> loop to <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>'s complex <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">loop</span></code> expressions. Moreover, the key issue that makes this an objective rather than subjective matter is that Scheme makes specific requirements for the handling of <a href="/wiki/Tail_call" title="Tail call">tail calls</a>, and thus the reason that the use of tail recursion is generally encouraged for Scheme is that the practice is expressly supported by the language definition. By contrast, ANSI Common Lisp does not require<sup id="cite_ref-51" class="reference"><a href="#cite_note-51">[51]</a></sup> the optimization commonly termed a tail call elimination. Thus, the fact that tail recursive style as a casual replacement for the use of more traditional <a href="/wiki/Iteration" title="Iteration">iteration</a> constructs (such as <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">do</span></code>, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">dolist</span></code> or <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">loop</span></code>) is discouraged<sup id="cite_ref-52" class="reference"><a href="#cite_note-52">[52]</a></sup> in Common Lisp is not just a matter of stylistic preference, but potentially one of efficiency (since an apparent tail call in Common Lisp may not compile as a simple <a href="/wiki/Branch_(computer_science)" title="Branch (computer science)">jump</a>) and program correctness (since tail recursion may increase stack use in Common Lisp, risking <a href="/wiki/Stack_overflow" title="Stack overflow">stack overflow</a>).
</p><p>Some Lisp control structures are <i>special operators</i>, equivalent to other languages' syntactic keywords. Expressions using these operators have the same surface appearance as function calls, but differ in that the arguments are not necessarily evaluated—or, in the case of an iteration expression, may be evaluated more than once.
</p><p>In contrast to most other major programming languages, Lisp allows implementing control structures using the language. Several control structures are implemented as Lisp macros, and can even be macro-expanded by the programmer who wants to know how they work.
</p><p>Both Common Lisp and Scheme have operators for non-local control flow. The differences in these operators are some of the deepest differences between the two dialects. Scheme supports <i>re-entrant <a href="/wiki/Continuation" title="Continuation">continuations</a></i> using the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">call/cc</span></code> procedure, which allows a program to save (and later restore) a particular place in execution. Common Lisp does not support re-entrant continuations, but does support several ways of handling escape continuations.
</p><p>Often, the same algorithm can be expressed in Lisp in either an imperative or a functional style. As noted above, Scheme tends to favor the functional style, using tail recursion and continuations to express control flow. However, imperative style is still quite possible. The style preferred by many Common Lisp programmers may seem more familiar to programmers used to structured languages such as C, while that preferred by Schemers more closely resembles pure-functional languages such as <a href="/wiki/Haskell_(programming_language)" title="Haskell (programming language)">Haskell</a>.
</p><p>Because of Lisp's early heritage in list processing, it has a wide array of higher-order functions relating to iteration over sequences. In many cases where an explicit loop would be needed in other languages (like a <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nv">for</span></code> loop in C) in Lisp the same task can be accomplished with a higher-order function. (The same is true of many functional programming languages.)
</p><p>A good example is a function which in Scheme is called <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">map</span></code> and in Common Lisp is called <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">mapcar</span></code>. Given a function and one or more lists, <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">mapcar</span></code> applies the function successively to the lists' elements in order, collecting the results in a new list:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">mapcar</span> <span class="nf">#'</span><span class="nb">+</span> <span class="o">'</span><span class="p">(</span><span class="mi">1</span> <span class="mi">2</span> <span class="mi">3</span> <span class="mi">4</span> <span class="mi">5</span><span class="p">)</span> <span class="o">'</span><span class="p">(</span><span class="mi">10</span> <span class="mi">20</span> <span class="mi">30</span> <span class="mi">40</span> <span class="mi">50</span><span class="p">))</span>
</pre></div>
<p>This applies the <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">+</span></code> function to each corresponding pair of list elements, yielding the result <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="p">(</span><span class="mi">11</span> <span class="mi">22</span> <span class="mi">33</span> <span class="mi">44</span> <span class="mi">55</span><span class="p">)</span></code>.
</p>
<h2><span class="mw-headline" id="Examples">Examples</span></h2>
<p>Here are examples of Common Lisp code.
</p><p>The basic "<a href="/wiki/Hello_world" class="mw-redirect" title="Hello world">Hello world</a>" program:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">print</span> <span class="s">"Hello world"</span><span class="p">)</span>
</pre></div>
<p>Lisp syntax lends itself naturally to recursion. Mathematical problems such as the enumeration of recursively defined sets are simple to express in this notation.
</p><p>Evaluate a number's <a href="/wiki/Factorial" title="Factorial">factorial</a>:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">defun</span> <span class="nv">factorial</span> <span class="p">(</span><span class="nv">n</span><span class="p">)</span>
<span class="p">(</span><span class="k">if</span> <span class="p">(</span><span class="nb">=</span> <span class="nv">n</span> <span class="mi">0</span><span class="p">)</span> <span class="mi">1</span>
<span class="p">(</span><span class="nb">*</span> <span class="nv">n</span> <span class="p">(</span><span class="nv">factorial</span> <span class="p">(</span><span class="nb">-</span> <span class="nv">n</span> <span class="mi">1</span><span class="p">)))))</span>
</pre></div>
<p>An alternative implementation takes less stack space than the previous version if the underlying Lisp system optimizes <a href="/wiki/Tail_recursion" class="mw-redirect" title="Tail recursion">tail recursion</a>:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">defun</span> <span class="nv">factorial</span> <span class="p">(</span><span class="nv">n</span> <span class="k">&optional</span> <span class="p">(</span><span class="nv">acc</span> <span class="mi">1</span><span class="p">))</span>
<span class="p">(</span><span class="k">if</span> <span class="p">(</span><span class="nb">=</span> <span class="nv">n</span> <span class="mi">0</span><span class="p">)</span> <span class="nv">acc</span>
<span class="p">(</span><span class="nv">factorial</span> <span class="p">(</span><span class="nb">-</span> <span class="nv">n</span> <span class="mi">1</span><span class="p">)</span> <span class="p">(</span><span class="nb">*</span> <span class="nv">acc</span> <span class="nv">n</span><span class="p">))))</span>
</pre></div>
<p>Contrast with an iterative version which uses <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>'s <code class="mw-highlight mw-highlight-lang-lisp" dir="ltr"><span class="nb">loop</span></code> macro:
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span> <span class="p">(</span><span class="nb">defun</span> <span class="nv">factorial</span> <span class="p">(</span><span class="nv">n</span><span class="p">)</span>
<span class="p">(</span><span class="nb">loop</span> <span class="nv">for</span> <span class="nv">i</span> <span class="nv">from</span> <span class="mi">1</span> <span class="nv">to</span> <span class="nv">n</span>
<span class="nv">for</span> <span class="nv">fac</span> <span class="nb">=</span> <span class="mi">1</span> <span class="nv">then</span> <span class="p">(</span><span class="nb">*</span> <span class="nv">fac</span> <span class="nv">i</span><span class="p">)</span>
<span class="nv">finally</span> <span class="p">(</span><span class="nb">return</span> <span class="nv">fac</span><span class="p">)))</span>
</pre></div>
<p>The following function reverses a list. (Lisp's built-in <i>reverse</i> function does the same thing.)
</p>
<div class="mw-highlight mw-highlight-lang-lisp mw-content-ltr" dir="ltr"><pre><span></span><span class="p">(</span><span class="nb">defun</span> <span class="nv">-reverse</span> <span class="p">(</span><span class="nb">list</span><span class="p">)</span>
<span class="p">(</span><span class="k">let</span> <span class="p">((</span><span class="nv">return-value</span> <span class="o">'</span><span class="p">()))</span>
<span class="p">(</span><span class="nb">dolist</span> <span class="p">(</span><span class="nv">e</span> <span class="nb">list</span><span class="p">)</span> <span class="p">(</span><span class="nb">push</span> <span class="nv">e</span> <span class="nv">return-value</span><span class="p">))</span>
<span class="nv">return-value</span><span class="p">))</span>
</pre></div>
<h2><span class="mw-headline" id="Object_systems">Object systems</span></h2>
<p>Various object systems and models have been built on top of, alongside, or into Lisp, including:
</p>
<ul><li>The <a href="/wiki/Common_Lisp_Object_System" title="Common Lisp Object System">Common Lisp Object System</a>, CLOS, is an integral part of ANSI Common Lisp. CLOS descended from New Flavors and CommonLOOPS. ANSI Common Lisp was the first standardized object-oriented programming language (1994, ANSI X3J13).</li>
<li>ObjectLisp<sup id="cite_ref-53" class="reference"><a href="#cite_note-53">[53]</a></sup> or <a href="/wiki/Object_Lisp" title="Object Lisp">Object Lisp</a>, used by <a href="/wiki/Lisp_Machines_Incorporated" class="mw-redirect" title="Lisp Machines Incorporated">Lisp Machines Incorporated</a> and early versions of Macintosh Common Lisp</li>
<li>LOOPS (Lisp Object-Oriented Programming System) and the later <a href="/wiki/CommonLOOPS" class="mw-redirect" title="CommonLOOPS">CommonLOOPS</a></li>
<li><a href="/wiki/Flavors_(computer_science)" class="mw-redirect" title="Flavors (computer science)">Flavors</a>, built at <a href="/wiki/Massachusetts_Institute_of_Technology" title="Massachusetts Institute of Technology">MIT</a>, and its descendant New Flavors (developed by <a href="/wiki/Symbolics" title="Symbolics">Symbolics</a>).</li>
<li>KR (short for Knowledge Representation), a <a href="/wiki/Constraint_satisfaction" title="Constraint satisfaction">constraints</a>-based object system developed to aid the writing of Garnet, a GUI library for <a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a>.</li>
<li><a href="/wiki/Knowledge_Engineering_Environment" title="Knowledge Engineering Environment">Knowledge Engineering Environment</a> (KEE) used an object system called UNITS and integrated it with an <a href="/wiki/Inference_engine" title="Inference engine">inference engine</a><sup id="cite_ref-54" class="reference"><a href="#cite_note-54">[54]</a></sup> and a <a href="/wiki/Truth_maintenance_systems" class="mw-redirect" title="Truth maintenance systems">truth maintenance system</a> (ATMS).</li></ul>
<h2><span class="mw-headline" id="See_also">See also</span></h2>
<ul><li><a href="/wiki/Self-modifying_code" title="Self-modifying code">Self-modifying code</a></li></ul>
<h2><span class="mw-headline" id="References">References</span></h2>
<div class="reflist columns references-column-width" style="-moz-column-width: 30em; -webkit-column-width: 30em; column-width: 30em; list-style-type: decimal;">
<ol class="references">
<li id="cite_note-MCCARTHY-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-MCCARTHY_1-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFJohn_McCarthy" class="citation web cs1">John McCarthy. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20131004215327/http://www-formal.stanford.edu/jmc/recursive.html">"Recursive Functions of Symbolic Expressions and Their Computation by Machine, Part I"</a>. Archived from <a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/recursive.html">the original</a> on 2013-10-04<span class="reference-accessdate">. Retrieved <span class="nowrap">2006-10-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Recursive+Functions+of+Symbolic+Expressions+and+Their+Computation+by+Machine%2C+Part+I&rft.au=John+McCarthy&rft_id=http%3A%2F%2Fwww-formal.stanford.edu%2Fjmc%2Frecursive.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><style data-mw-deduplicate="TemplateStyles:r951705291">.mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .id-lock-free a,.mw-parser-output .citation .cs1-lock-free a{background-image:url("/media/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png");background-image:linear-gradient(transparent,transparent),url("/media/wikipedia/commons/6/65/Lock-green.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center}.mw-parser-output .id-lock-limited a,.mw-parser-output .id-lock-registration a,.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background-image:url("/media/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png");background-image:linear-gradient(transparent,transparent),url("/media/wikipedia/commons/d/d6/Lock-gray-alt-2.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center}.mw-parser-output .id-lock-subscription a,.mw-parser-output .citation .cs1-lock-subscription a{background-image:url("/media/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png");background-image:linear-gradient(transparent,transparent),url("/media/wikipedia/commons/a/aa/Lock-red-alt-2.svg");background-repeat:no-repeat;background-size:9px;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background-image:url("/media/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png");background-image:linear-gradient(transparent,transparent),url("/media/wikipedia/commons/4/4c/Wikisource-logo.svg");background-repeat:no-repeat;background-size:12px;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}</style></span>
</li>
<li id="cite_note-SMITH-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-SMITH_2-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFDavid_Canfield_Smith" class="citation web cs1">David Canfield Smith. <a rel="nofollow" class="external text" href="http://www.softwarepreservation.org/projects/LISP/stanford/Smith-MLISP-AIM-84.pdf">"MLISP Users Manual"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2006-10-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=MLISP+Users+Manual&rft.au=David+Canfield+Smith&rft_id=http%3A%2F%2Fwww.softwarepreservation.org%2Fprojects%2FLISP%2Fstanford%2FSmith-MLISP-AIM-84.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite id="CITEREFJohn_McCarthy1979" class="citation web cs1">John McCarthy (12 February 1979). <a rel="nofollow" class="external text" href="http://jmc.stanford.edu/articles/lisp/lisp.pdf">"History of Lisp: Artificial Intelligence Laboratory"</a> <span class="cs1-format">(PDF)</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=History+of+Lisp%3A+Artificial+Intelligence+Laboratory&rft.date=1979-02-12&rft.au=John+McCarthy&rft_id=http%3A%2F%2Fjmc.stanford.edu%2Farticles%2Flisp%2Flisp.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">According to what reported by <a href="/wiki/Paul_Graham_(computer_programmer)" class="mw-redirect" title="Paul Graham (computer programmer)">Paul Graham</a> in <i><a href="/wiki/Hackers_%26_Painters" title="Hackers & Painters">Hackers & Painters</a></i>, p. 185, McCarthy said: "Steve Russell said, look, why don't I program this <i>eval</i> ... and I said to him, ho, ho, you're confusing theory with practice, this <i>eval</i> is intended for reading, not for computing. But he went ahead and did it. That is, he compiled the <i>eval</i> in my paper into <a href="/wiki/IBM_704" title="IBM 704">IBM 704</a> machine code, fixing <a href="/wiki/Software_bug" title="Software bug">bug</a>, and then advertised this as a Lisp interpreter, which it certainly was. So at that point Lisp had essentially the form that it has today ..."</span>
</li>
<li id="cite_note-PREHISTORY-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-PREHISTORY_5-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFJohn_McCarthy" class="citation web cs1">John McCarthy. <a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/history/lisp/node2.html">"LISP prehistory - Summer 1956 through Summer 1958"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2010-03-14</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=LISP+prehistory+-+Summer+1956+through+Summer+1958&rft.au=John+McCarthy&rft_id=http%3A%2F%2Fwww-formal.stanford.edu%2Fjmc%2Fhistory%2Flisp%2Fnode2.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-LEVIN-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-LEVIN_6-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFTim_Hart_and_Mike_Levin" class="citation web cs1">Tim Hart and Mike Levin. <a rel="nofollow" class="external text" href="ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-039.pdf">"AI Memo 39-The new compiler"</a> <span class="cs1-format">(PDF)</span><span class="reference-accessdate">. Retrieved <span class="nowrap">2019-03-18</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=AI+Memo+39-The+new+compiler&rft.au=Tim+Hart+and+Mike+Levin&rft_id=ftp%3A%2F%2Fpublications.ai.mit.edu%2Fai-publications%2Fpdf%2FAIM-039.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-1.5_manual-7"><span class="mw-cite-backlink">^ <a href="#cite_ref-1.5_manual_7-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-1.5_manual_7-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFMcCarthyAbrahamsEdwardsHart1985" class="citation book cs1">McCarthy, John; Abrahams, Paul W.; Edwards, Daniel J.; Hart, Timothy P.; Levin, Michael I. (1985) [1962]. <span class="cs1-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/lisp15programmer00john"><i>LISP 1.5 Programmer's Manual</i></a></span> (2nd ed.). <a href="/wiki/MIT_Press" title="MIT Press">MIT Press</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-262-13011-4" title="Special:BookSources/0-262-13011-4"><bdi>0-262-13011-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=LISP+1.5+Programmer%27s+Manual&rft.edition=2nd&rft.pub=MIT+Press&rft.date=1985&rft.isbn=0-262-13011-4&rft.aulast=McCarthy&rft.aufirst=John&rft.au=Abrahams%2C+Paul+W.&rft.au=Edwards%2C+Daniel+J.&rft.au=Hart%2C+Timothy+P.&rft.au=Levin%2C+Michael+I.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Flisp15programmer00john&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text">The 36-bit word size of the <a href="/wiki/PDP-6" title="PDP-6">PDP-6</a>/<a href="/wiki/PDP-10" title="PDP-10">PDP-10</a> was influenced by the usefulness of having two Lisp 18-bit pointers in a single word. <cite id="CITEREFPeter_J._Hurley1990" class="citation newsgroup cs1">Peter J. Hurley (18 October 1990). <a rel="nofollow" class="external text" href="https://groups.google.com/group/alt.folklore.computers/browse_thread/thread/6e5602ce733d0ec/17597705ae289112">"The History of TOPS or Life in the Fast ACs"</a>. <a href="/wiki/Usenet_newsgroup" title="Usenet newsgroup">Newsgroup</a>: <a rel="nofollow" class="external text" href="news:alt.folklore.computers">alt.folklore.computers</a>. <a href="/wiki/Usenet_(identifier)" class="mw-redirect" title="Usenet (identifier)">Usenet:</a> <a rel="nofollow" class="external text" href="news:84950@tut.cis.ohio-state.edu">84950@tut.cis.ohio-state.edu</a>. <q>The PDP-6 project started in early 1963, as a 24-bit machine. It grew to 36 bits for LISP, a design goal.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+History+of+TOPS+or+Life+in+the+Fast+ACs&rft.pub=alt.folklore.computers&rft.date=1990-10-18&rft_id=news%3A84950%40tut.cis.ohio-state.edu&rft.au=Peter+J.+Hurley&rft_id=http%3A%2F%2Fgroups.google.com%2Fgroup%2Falt.folklore.computers%2Fbrowse_thread%2Fthread%2F6e5602ce733d0ec%2F17597705ae289112&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Common Lisp: <code>(defun f (x) x)</code><br />Scheme: <code>(define f (lambda (x) x))</code> or <code>(define (f x) x)</code></span>
</li>
<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><cite id="CITEREFMcCarthyBraytonEdwardsFox1960" class="citation journal cs1"><a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">McCarthy, J.</a>; <a href="/w/index.php?title=Robert_Brayton_(computer_scientist)&action=edit&redlink=1" class="new" title="Robert Brayton (computer scientist) (page does not exist)">Brayton, R.</a>; <a href="/w/index.php?title=Daniel_Edwards_(programmer)&action=edit&redlink=1" class="new" title="Daniel Edwards (programmer) (page does not exist)">Edwards, D.</a>; <a href="/wiki/Phyllis_Fox" title="Phyllis Fox">Fox, P.</a>; <a href="/wiki/Louis_Hodes" title="Louis Hodes">Hodes, L.</a>; <a href="/wiki/David_Luckham" title="David Luckham">Luckham, D.</a>; <a href="/w/index.php?title=Klim_Maling_(programmer)&action=edit&redlink=1" class="new" title="Klim Maling (programmer) (page does not exist)">Maling, K.</a>; <a href="/wiki/David_Park_(computer_scientist)" title="David Park (computer scientist)">Park, D.</a>; <a href="/wiki/Steve_Russell_(computer_scientist)" title="Steve Russell (computer scientist)">Russell, S.</a> (March 1960). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100717111134/http://history.siam.org/sup/Fox_1960_LISP.pdf">"LISP I Programmers Manual"</a> <span class="cs1-format">(PDF)</span>. <a href="/wiki/Boston" title="Boston">Boston</a>, <a href="/wiki/Massachusetts" title="Massachusetts">Massachusetts</a>: Artificial Intelligence Group, <a href="/wiki/M.I.T._Computation_Center" class="mw-redirect" title="M.I.T. Computation Center">M.I.T. Computation Center</a> and <a href="/wiki/Research_Laboratory_of_Electronics_at_MIT" title="Research Laboratory of Electronics at MIT">Research Laboratory</a>. Archived from <a rel="nofollow" class="external text" href="http://history.siam.org/sup/Fox_1960_LISP.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2010-07-17.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=LISP+I+Programmers+Manual&rft.date=1960-03&rft.aulast=McCarthy&rft.aufirst=J.&rft.au=Brayton%2C+R.&rft.au=Edwards%2C+D.&rft.au=Fox%2C+P.&rft.au=Hodes%2C+L.&rft.au=Luckham%2C+D.&rft.au=Maling%2C+K.&rft.au=Park%2C+D.&rft.au=Russell%2C+S.&rft_id=http%3A%2F%2Fhistory.siam.org%2Fsup%2FFox_1960_LISP.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span> <span class="cs1-hidden-error error citation-comment">Cite journal requires <code class="cs1-code">|journal=</code> (<a href="/wiki/Help:CS1_errors#missing_periodical" title="Help:CS1 errors">help</a>)</span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/> Accessed May 11, 2010.</span>
</li>
<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite id="CITEREFQuamDiffle" class="citation book cs1">Quam, Lynn H.; Diffle, Whitfield. <a rel="nofollow" class="external text" href="http://www.softwarepreservation.org/projects/LISP/stanford/SAILON-28.6.pdf"><i>Stanford LISP 1.6 Manual</i></a> <span class="cs1-format">(PDF)</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Stanford+LISP+1.6+Manual&rft.aulast=Quam&rft.aufirst=Lynn+H.&rft.au=Diffle%2C+Whitfield&rft_id=http%3A%2F%2Fwww.softwarepreservation.org%2Fprojects%2FLISP%2Fstanford%2FSAILON-28.6.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20071214064433/http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt">"Maclisp Reference Manual"</a>. March 3, 1979. Archived from <a rel="nofollow" class="external text" href="http://zane.brouhaha.com/~healyzh/doc/lisp.doc.txt">the original</a> on 2007-12-14.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Maclisp+Reference+Manual&rft.date=1979-03-03&rft_id=http%3A%2F%2Fzane.brouhaha.com%2F~healyzh%2Fdoc%2Flisp.doc.txt&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text"><cite id="CITEREFTeitelman1974" class="citation book cs1">Teitelman, Warren (1974). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060602134835/http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf"><i>InterLisp Reference Manual</i></a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.bitsavers.org/pdf/xerox/interlisp/1974_InterlispRefMan.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2006-06-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2006-08-19</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=InterLisp+Reference+Manual&rft.date=1974&rft.aulast=Teitelman&rft.aufirst=Warren&rft_id=http%3A%2F%2Fwww.bitsavers.org%2Fpdf%2Fxerox%2Finterlisp%2F1974_InterlispRefMan.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://hal.archives-ouvertes.fr/file/index/docid/70041/filename/RT-0126.pdf">Outils de generation d’interfaces : etat de l’art et classification by H. El Mrabet</a></span>
</li>
<li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external free" href="ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf">ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-349.pdf</a><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link since December 2017">permanent dead link</span></a></i>]</span></sup></span>
</li>
<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><cite id="CITEREFSteele" class="citation book cs1">Steele, Guy L., Jr. <a rel="nofollow" class="external text" href="https://www.cs.cmu.edu/Groups/AI/html/cltl/clm/node6.html">"Purpose"</a>. <i>Common Lisp the Language</i> (2nd ed.). <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-13-152414-3" title="Special:BookSources/0-13-152414-3"><bdi>0-13-152414-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Purpose&rft.btitle=Common+Lisp+the+Language&rft.edition=2nd&rft.isbn=0-13-152414-3&rft.aulast=Steele&rft.aufirst=Guy+L.%2C+Jr.&rft_id=https%3A%2F%2Fwww.cs.cmu.edu%2FGroups%2FAI%2Fhtml%2Fcltl%2Fclm%2Fnode6.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><cite id="CITEREFKantrowitzMargolin1996" class="citation web cs1">Kantrowitz, Mark; Margolin, Barry (20 February 1996). <a rel="nofollow" class="external text" href="https://www.cs.cmu.edu/Groups/AI/html/faqs/lang/lisp/part2/faq-doc-13.html">"History: Where did Lisp come from?"</a>. <i>FAQ: Lisp Frequently Asked Questions 2/7</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=FAQ%3A+Lisp+Frequently+Asked+Questions+2%2F7&rft.atitle=History%3A+Where+did+Lisp+come+from%3F&rft.date=1996-02-20&rft.aulast=Kantrowitz&rft.aufirst=Mark&rft.au=Margolin%2C+Barry&rft_id=https%3A%2F%2Fwww.cs.cmu.edu%2FGroups%2FAI%2Fhtml%2Ffaqs%2Flang%2Flisp%2Fpart2%2Ffaq-doc-13.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=22987">"ISO/IEC 13816:1997"</a>. Iso.org. 2007-10-01<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-11-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=ISO%2FIEC+13816%3A1997&rft.pub=Iso.org&rft.date=2007-10-01&rft_id=http%3A%2F%2Fwww.iso.org%2Fiso%2Fiso_catalogue%2Fcatalogue_tc%2Fcatalogue_detail.htm%3Fcsnumber%3D22987&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=44338">"ISO/IEC 13816:2007"</a>. Iso.org. 2013-10-30<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-11-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=ISO%2FIEC+13816%3A2007&rft.pub=Iso.org&rft.date=2013-10-30&rft_id=http%3A%2F%2Fwww.iso.org%2Fiso%2Fiso_catalogue%2Fcatalogue_tc%2Fcatalogue_detail.htm%3Fcsnumber%3D44338&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.nhplace.com/kent/CL/x3j13-86-020.html">"X3J13 Charter"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=X3J13+Charter&rft_id=http%3A%2F%2Fwww.nhplace.com%2Fkent%2FCL%2Fx3j13-86-020.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20061004031130/http://wiki.alu.org/The_Road_To_Lisp_Survey">"The Road To Lisp Survey"</a>. Archived from <a rel="nofollow" class="external text" href="http://wiki.alu.org/The_Road_To_Lisp_Survey">the original</a> on 2006-10-04<span class="reference-accessdate">. Retrieved <span class="nowrap">2006-10-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Road+To+Lisp+Survey&rft_id=http%3A%2F%2Fwiki.alu.org%2FThe_Road_To_Lisp_Survey&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.faqs.org/docs/artu/ch14s05.html">"Trends for the Future"</a>. Faqs.org<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-11-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Trends+for+the+Future&rft.pub=Faqs.org&rft_id=http%3A%2F%2Fwww.faqs.org%2Fdocs%2Fartu%2Fch14s05.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><cite id="CITEREFWeinreb" class="citation web cs1">Weinreb, Daniel. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120421181340/http://common-lisp.net/~dlw/LispSurvey.html#">"Common Lisp Implementations: A Survey"</a>. Archived from <a rel="nofollow" class="external text" href="http://common-lisp.net/~dlw/LispSurvey.html">the original</a> on 2012-04-21<span class="reference-accessdate">. Retrieved <span class="nowrap">4 April</span> 2012</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Common+Lisp+Implementations%3A+A+Survey&rft.aulast=Weinreb&rft.aufirst=Daniel&rft_id=http%3A%2F%2Fcommon-lisp.net%2F~dlw%2FLispSurvey.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.lisp50.org/">"LISP50@OOPSLA"</a>. Lisp50.org<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-11-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=LISP50%40OOPSLA&rft.pub=Lisp50.org&rft_id=http%3A%2F%2Fwww.lisp50.org%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.schemers.org/Documents/Standards/R5RS/">Documents: Standards: R5RS</a>. schemers.org (2012-01-11). Retrieved on 2013-07-17.</span>
</li>
<li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="http://cemerick.com/2009/03/24/why-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program/">"Why MIT now uses python instead of scheme for its undergraduate CS program"</a>. <i>cemerick.com</i>. March 24, 2009<span class="reference-accessdate">. Retrieved <span class="nowrap">November 10,</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=cemerick.com&rft.atitle=Why+MIT+now+uses+python+instead+of+scheme+for+its+undergraduate+CS+program&rft.date=2009-03-24&rft_id=http%3A%2F%2Fcemerick.com%2F2009%2F03%2F24%2Fwhy-mit-now-uses-python-instead-of-scheme-for-its-undergraduate-cs-program%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text"><cite id="CITEREFBroder2008" class="citation news cs1">Broder, Evan (January 8, 2008). <a rel="nofollow" class="external text" href="http://mitadmissions.org/blogs/entry/the_end_of_an_era_1">"The End of an Era"</a>. <i>mitadmissions.org</i><span class="reference-accessdate">. Retrieved <span class="nowrap">November 10,</span> 2013</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=mitadmissions.org&rft.atitle=The+End+of+an+Era&rft.date=2008-01-08&rft.aulast=Broder&rft.aufirst=Evan&rft_id=http%3A%2F%2Fmitadmissions.org%2Fblogs%2Fentry%2Fthe_end_of_an_era_1&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-MITEECS-Python-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-MITEECS-Python_28-0">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.eecs.mit.edu/academics-admissions/undergraduate-programs">"MIT EECS Undergraduate Programs"</a>. <i>www.eecs.mit.edu</i>. MIT Electrical Engineering & Computer Science<span class="reference-accessdate">. Retrieved <span class="nowrap">31 December</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.eecs.mit.edu&rft.atitle=MIT+EECS+Undergraduate+Programs&rft_id=https%3A%2F%2Fwww.eecs.mit.edu%2Facademics-admissions%2Fundergraduate-programs&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-MITx-Phyton-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-MITx-Phyton_29-0">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.eecs.mit.edu/news-events/announcements/mitx-introductory-python-course-hits-12-million-enrollments">"MITx introductory Python course hits 1.2 million enrollments"</a>. <i>MIT EECS</i>. MIT Electrical Engineering & Computer Science<span class="reference-accessdate">. Retrieved <span class="nowrap">31 December</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MIT+EECS&rft.atitle=MITx+introductory+Python+course+hits+1.2+million+enrollments&rft_id=https%3A%2F%2Fwww.eecs.mit.edu%2Fnews-events%2Fannouncements%2Fmitx-introductory-python-course-hits-12-million-enrollments&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text">Chapter 1.1.2, History, ANSI CL Standard</span>
</li>
<li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external autonumber" href="https://www.cliki.net/Clasp">[1]</a> Clasp is a Common Lisp implementation that interoperates with C++ and uses LLVM for <a href="/wiki/Just-in-time_compilation" title="Just-in-time compilation">just-in-time compilation</a> (JIT) to native code.</span>
</li>
<li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external autonumber" href="https://common-lisp.net/project/armedbear/">[2]</a> "Armed Bear Common Lisp (ABCL) is a full implementation of the Common Lisp language featuring both an interpreter and a compiler, running in the JVM"</span>
</li>
<li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external autonumber" href="https://common-lisp.net/~dlw/LispSurvey.html">[3]</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20180622083812/https://common-lisp.net/~dlw/LispSurvey.html#">Archived</a> 2018-06-22 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> Common Lisp Implementations: A Survey</span>
</li>
<li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external autonumber" href="https://www.cliki.net/Common+Lisp+implementation">[4]</a> Comparison of actively developed Common Lisp implementations</span>
</li>
<li id="cite_note-clojure-immutability-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-clojure-immutability_35-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.infoq.com/articles/in-depth-look-clojure-collections">An In-Depth Look at Clojure Collections</a>, Retrieved 2012-06-24</span>
</li>
<li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://clojure.org/about/rationale">"Clojure rational"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">27 August</span> 2019</span>. <q>Clojure is a Lisp not constrained by backwards compatibility</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Clojure+rational&rft_id=https%3A%2F%2Fclojure.org%2Fabout%2Frationale&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-script-fu-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-script-fu_37-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.gimp.org/docs/script-fu-update.html">Script-fu In GIMP 2.4</a>, Retrieved 2009-10-29</span>
</li>
<li id="cite_note-librep-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-librep_38-0">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://sawfish.wikia.com/wiki/Librep">librep</a> at Sawfish Wikia, retrieved 2009-10-29</span>
</li>
<li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://standards.ieee.org/standard/1178-1990.html">"IEEE Scheme"</a>. <i>IEEE 1178-1990 - IEEE Standard for the Scheme Programming Language</i><span class="reference-accessdate">. Retrieved <span class="nowrap">27 August</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IEEE+1178-1990+-+IEEE+Standard+for+the+Scheme+Programming+Language&rft.atitle=IEEE+Scheme&rft_id=https%3A%2F%2Fstandards.ieee.org%2Fstandard%2F1178-1990.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/history/lisp/node2.html">"LISP prehistory - Summer 1956 through Summer 1958"</a>. <q>I invented conditional expressions in connection with a set of chess legal move routines I wrote in FORTRAN for the IBM 704 at M.I.T. during 1957–58 ... A paper defining conditional expressions and proposing their use in Algol was sent to the Communications of the ACM but was arbitrarily demoted to a letter to the editor, because it was very short.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=LISP+prehistory+-+Summer+1956+through+Summer+1958.&rft_id=http%3A%2F%2Fwww-formal.stanford.edu%2Fjmc%2Fhistory%2Flisp%2Fnode2.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://userpage.fu-berlin.de/~ram/pub/pub_jf47ht81Ht/doc_kay_oop_en">"Meaning of 'Object-Oriented Programming' According to Dr. Alan Kay"</a>. 2003-07-23. <q>I didn't understand the monster LISP idea of tangible metalanguage then, but got kind of close with ideas about extensible languages ... The second phase of this was to finally understand LISP and then using this understanding to make much nicer and smaller and more powerful and more late bound understructures ... OOP to me means only messaging, local retention and protection and hiding of state-process, and extreme late-binding of all things. It can be done in Smalltalk and in LISP. There are possibly other systems in which this is possible, but I'm not aware of them.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Meaning+of+%27Object-Oriented+Programming%27+According+to+Dr.+Alan+Kay&rft.date=2003-07-23&rft_id=http%3A%2F%2Fuserpage.fu-berlin.de%2F~ram%2Fpub%2Fpub_jf47ht81Ht%2Fdoc_kay_oop_en&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text"><cite id="CITEREFLiebermanHewitt1983" class="citation cs2">Lieberman, Henry; Hewitt, Carl (June 1983), <a rel="nofollow" class="external text" href="http://web.media.mit.edu/~lieber/Lieberary/GC/Realtime/Realtime.html">"A Real-Time Garbage Collector Based on the Lifetimes of Objects"</a>, <i>Communications of the ACM</i>, <b>26</b> (6): 419–429, <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <span class="cs1-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="//citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.8633">10.1.1.4.8633</a></span>, <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1145%2F358141.358147">10.1145/358141.358147</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Communications+of+the+ACM&rft.atitle=A+Real-Time+Garbage+Collector+Based+on+the+Lifetimes+of+Objects&rft.volume=26&rft.issue=6&rft.pages=419-429&rft.date=1983-06&rft_id=%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.4.8633&rft_id=info%3Adoi%2F10.1145%2F358141.358147&rft.aulast=Lieberman&rft.aufirst=Henry&rft.au=Hewitt%2C+Carl&rft_id=http%3A%2F%2Fweb.media.mit.edu%2F~lieber%2FLieberary%2FGC%2FRealtime%2FRealtime.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"><cite id="CITEREFEdsger_W._Dijkstra1972" class="citation cs2">Edsger W. Dijkstra (1972), <a rel="nofollow" class="external text" href="http://www.cs.utexas.edu/~EWD/transcriptions/EWD03xx/EWD340.html"><i>The Humble Programmer (EWD 340)</i></a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Humble+Programmer+%28EWD+340%29&rft.date=1972&rft.au=Edsger+W.+Dijkstra&rft_id=http%3A%2F%2Fwww.cs.utexas.edu%2F~EWD%2Ftranscriptions%2FEWD03xx%2FEWD340.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/> (ACM Turing Award lecture).</span>
</li>
<li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.linkedin.com/pulse/look-clojure-lisp-resurgence-todd-towles">"A Look at Clojure and the Lisp Resurgence"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=A+Look+at+Clojure+and+the+Lisp+Resurgence&rft_id=https%3A%2F%2Fwww.linkedin.com%2Fpulse%2Flook-clojure-lisp-resurgence-todd-towles&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-LEVIN2-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-LEVIN2_45-0">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.catb.org/~esr/jargon/html/L/LISP.html">"The Jargon File - Lisp"</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2006-10-13</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Jargon+File+-+Lisp&rft_id=http%3A%2F%2Fwww.catb.org%2F~esr%2Fjargon%2Fhtml%2FL%2FLISP.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-SebestaLanguages-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-SebestaLanguages_46-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFSebesta2012" class="citation book cs1">Sebesta, Robert W. (2012). "<span class="cs1-kern-left">"</span>2.4 Functional Programming: LISP";"6.9 List Types";"15.4 The First Functional Programming Language: LISP<span class="cs1-kern-right">"</span>". <a rel="nofollow" class="external text" href="https://www.pearson.com/us/higher-education/product/Sebesta-Concepts-of-Programming-Languages-10th-Edition/9780131395312.html"><i>Concepts of Programming Languages</i></a> <span class="cs1-format">(print)</span> (10th ed.). Boston, MA, USA: Addison-Wesley. pp. 47–52, 281–284, 677–680. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-13-139531-2" title="Special:BookSources/978-0-13-139531-2"><bdi>978-0-13-139531-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=%222.4+Functional+Programming%3A+LISP%22%3B%226.9+List+Types%22%3B%2215.4+The+First+Functional+Programming+Language%3A+LISP%22&rft.btitle=Concepts+of+Programming+Languages&rft.place=Boston%2C+MA%2C+USA&rft.pages=47-52%2C+281-284%2C+677-680&rft.edition=10th&rft.pub=Addison-Wesley&rft.date=2012&rft.isbn=978-0-13-139531-2&rft.aulast=Sebesta&rft.aufirst=Robert+W.&rft_id=https%3A%2F%2Fwww.pearson.com%2Fus%2Fhigher-education%2Fproduct%2FSebesta-Concepts-of-Programming-Languages-10th-Edition%2F9780131395312.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text">NB: a so-called "dotted list" is only one kind of "improper list". The other kind is the "circular list" where the cons cells form a loop. Typically this is represented using #n=(...) to represent the target cons cell that will have multiple references, and #n# is used to refer to this cons. For instance, (#1=(a b) . #1#) would normally be printed as ((a b) a b) (without circular structure printing enabled), but makes the reuse of the cons cell clear. #1=(a . #1#) cannot normally be printed as it is circular, although (a...) is sometimes displayed, the CDR of the cons cell defined by #1= is itself.</span>
</li>
<li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.cs.washington.edu/education/courses/cse341/04wi/lectures/14-scheme-quote.html">"CSE 341: Scheme: Quote, Quasiquote, and Metaprogramming"</a>. Cs.washington.edu. 1999-02-22<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-11-15</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=CSE+341%3A+Scheme%3A+Quote%2C+Quasiquote%2C+and+Metaprogramming&rft.pub=Cs.washington.edu&rft.date=1999-02-22&rft_id=http%3A%2F%2Fwww.cs.washington.edu%2Feducation%2Fcourses%2Fcse341%2F04wi%2Flectures%2F14-scheme-quote.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></span>
</li>
<li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf">Quasiquotation in Lisp</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130603114956/http://repository.readscheme.org/ftp/papers/pepm99/bawden.pdf">Archived</a> 2013-06-03 at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, Alan Bawden</span>
</li>
<li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.gnu.org/software/emacs/manual/html_node/cl/Time-of-Evaluation.html">Time of Evaluation - Common Lisp Extensions</a>. Gnu.org. Retrieved on 2013-07-17.</span>
</li>
<li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.lispworks.com/documentation/HyperSpec/Body/03_bbc.htm">3.2.2.3 Semantic Constraints</a> in <a rel="nofollow" class="external text" href="http://www.lispworks.com/documentation/HyperSpec/Front/index.htm"><i>Common Lisp HyperSpec</i></a></span>
</li>
<li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text">4.3. Control Abstraction (Recursion vs. Iteration) in <a rel="nofollow" class="external text" href="http://www.cs.umd.edu/~nau/cmsc421/norvig-lisp-style.pdf">Tutorial on Good Lisp Programming Style</a> by <a href="/wiki/Kent_Pitman" title="Kent Pitman">Kent Pitman</a> and <a href="/wiki/Peter_Norvig" title="Peter Norvig">Peter Norvig</a>, August, 1993.</span>
</li>
<li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text">pg 17 of Bobrow 1986</span>
</li>
<li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text">Veitch, p 108, 1988</span>
</li>
</ol></div>
<h2><span class="mw-headline" id="Further_reading">Further reading</span></h2>
<style data-mw-deduplicate="TemplateStyles:r886047268">.mw-parser-output .refbegin{font-size:90%;margin-bottom:0.5em}.mw-parser-output .refbegin-hanging-indents>ul{list-style-type:none;margin-left:0}.mw-parser-output .refbegin-hanging-indents>ul>li,.mw-parser-output .refbegin-hanging-indents>dl>dd{margin-left:0;padding-left:3.2em;text-indent:-3.2em;list-style:none}.mw-parser-output .refbegin-100{font-size:100%}</style><div class="refbegin reflist" style="">
<ul><li><cite id="CITEREFMcCarthy1979" class="citation web cs1">McCarthy, John (1979-02-12). <a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/history/lisp/node3.html">"The implementation of Lisp"</a>. <i>History of Lisp</i>. Stanford University<span class="reference-accessdate">. Retrieved <span class="nowrap">2008-10-17</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=History+of+Lisp&rft.atitle=The+implementation+of+Lisp&rft.date=1979-02-12&rft.aulast=McCarthy&rft.aufirst=John&rft_id=http%3A%2F%2Fwww-formal.stanford.edu%2Fjmc%2Fhistory%2Flisp%2Fnode3.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><cite id="CITEREFSteele,_Jr.Richard_P._Gabriel1993" class="citation conference cs1">Steele, Jr., Guy L.; Richard P. Gabriel (1993). <a rel="nofollow" class="external text" href="http://www.dreamsongs.com/NewFiles/HOPL2-Uncut.pdf"><i>The evolution of Lisp</i></a> <span class="cs1-format">(PDF)</span>. The second ACM SIGPLAN conference on History of programming languages. New York, NY: ACM. pp. 231–270. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-89791-570-4" title="Special:BookSources/0-89791-570-4"><bdi>0-89791-570-4</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">2008-10-17</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=The+evolution+of+Lisp&rft.place=New+York%2C+NY&rft.pages=231-270&rft.pub=ACM&rft.date=1993&rft.isbn=0-89791-570-4&rft.aulast=Steele%2C+Jr.&rft.aufirst=Guy+L.&rft.au=Richard+P.+Gabriel&rft_id=http%3A%2F%2Fwww.dreamsongs.com%2FNewFiles%2FHOPL2-Uncut.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><cite id="CITEREFVeitch1998" class="citation book cs1">Veitch, Jim (1998). "A history and description of CLOS". In Salus, Peter H (ed.). <a rel="nofollow" class="external text" href="https://archive.org/details/handbookofprogra0000unse/page/107"><i>Handbook of programming languages</i></a>. Volume IV, Functional and logic programming languages (first ed.). Indianapolis, IN: Macmillan Technical Publishing. pp. <a rel="nofollow" class="external text" href="https://archive.org/details/handbookofprogra0000unse/page/107">107–158</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/1-57870-011-6" title="Special:BookSources/1-57870-011-6"><bdi>1-57870-011-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=A+history+and+description+of+CLOS&rft.btitle=Handbook+of+programming+languages&rft.place=Indianapolis%2C+IN&rft.pages=107-158&rft.edition=first&rft.pub=Macmillan+Technical+Publishing&rft.date=1998&rft.isbn=1-57870-011-6&rft.aulast=Veitch&rft.aufirst=Jim&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fhandbookofprogra0000unse%2Fpage%2F107&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><cite id="CITEREFAbelsonSussmanSussman1996" class="citation book cs1"><a href="/wiki/Harold_Abelson" class="mw-redirect" title="Harold Abelson">Abelson, Harold</a>; <a href="/wiki/Gerald_Jay_Sussman" title="Gerald Jay Sussman">Sussman, Gerald Jay</a>; <a href="/wiki/Julie_Sussman" class="mw-redirect" title="Julie Sussman">Sussman, Julie</a> (1996). <i><a href="/wiki/Structure_and_Interpretation_of_Computer_Programs" title="Structure and Interpretation of Computer Programs">Structure and Interpretation of Computer Programs</a></i> (2nd ed.). MIT Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-262-01153-0" title="Special:BookSources/0-262-01153-0"><bdi>0-262-01153-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Structure+and+Interpretation+of+Computer+Programs&rft.edition=2nd&rft.pub=MIT+Press&rft.date=1996&rft.isbn=0-262-01153-0&rft.aulast=Abelson&rft.aufirst=Harold&rft.au=Sussman%2C+Gerald+Jay&rft.au=Sussman%2C+Julie&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><a rel="nofollow" class="external text" href="https://www.gnu.org/gnu/rms-lisp.html">My Lisp Experiences and the Development of GNU Emacs</a>, <a href="/wiki/Transcription_(linguistics)" title="Transcription (linguistics)">transcript</a> of <a href="/wiki/Richard_Stallman" title="Richard Stallman">Richard Stallman</a>'s speech, 28 October 2002, at the <a href="/w/index.php?title=International_Lisp_Conference&action=edit&redlink=1" class="new" title="International Lisp Conference (page does not exist)">International Lisp Conference</a></li>
<li><cite id="CITEREFGraham2004" class="citation book cs1"><a href="/wiki/Paul_Graham_(computer_programmer)" class="mw-redirect" title="Paul Graham (computer programmer)">Graham, Paul</a> (2004). <i><a href="/wiki/Hackers_%26_Painters" title="Hackers & Painters"> Hackers & Painters. Big Ideas from the Computer Age</a></i>. O'Reilly. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-596-00662-4" title="Special:BookSources/0-596-00662-4"><bdi>0-596-00662-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Hackers+%26+Painters.+Big+Ideas+from+the+Computer+Age&rft.pub=O%27Reilly&rft.date=2004&rft.isbn=0-596-00662-4&rft.aulast=Graham&rft.aufirst=Paul&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li>
<li><cite id="CITEREFBerkeleyBobrow1964" class="citation book cs1"><a href="/wiki/Edmund_Berkeley" title="Edmund Berkeley">Berkeley, Edmund C.</a>; <a href="/wiki/Daniel_G._Bobrow" title="Daniel G. Bobrow">Bobrow, Daniel G.</a>, eds. (March 1964). <a rel="nofollow" class="external text" href="http://www.softwarepreservation.org/projects/LISP/book/III_LispBook_Apr66.pdf"><i>The Programming Language LISP: Its Operation and Applications</i></a> <span class="cs1-format">(PDF)</span>. Cambridge, Massachusetts: MIT Press.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Programming+Language+LISP%3A+Its+Operation+and+Applications&rft.place=Cambridge%2C+Massachusetts&rft.pub=MIT+Press&rft.date=1964-03&rft_id=http%3A%2F%2Fwww.softwarepreservation.org%2Fprojects%2FLISP%2Fbook%2FIII_LispBook_Apr66.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/>
<ul><li>Article largely based on the <i>LISP - A Simple Introduction</i> chapter: <cite id="CITEREFBerkeley1964" class="citation journal cs1">Berkeley, Edmund C. (Sep 1964). <a rel="nofollow" class="external text" href="https://archive.org/details/bitsavers_computersA_6908895">"THE PROGRAMMING LANGUAGE LISP: AN INTRODUCTION AND APPRAISAL"</a>. <i>Computers and Automation</i>: <a rel="nofollow" class="external text" href="https://archive.org/details/bitsavers_computersA_6908895/page/n15">16</a>-23.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Computers+and+Automation&rft.atitle=THE+PROGRAMMING+LANGUAGE+LISP%3A+AN+INTRODUCTION+AND+APPRAISAL&rft.pages=16-23&rft.date=1964-09&rft.aulast=Berkeley&rft.aufirst=Edmund+C.&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fbitsavers_computersA_6908895&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li></ul></li>
<li><cite id="CITEREFWeissman1967" class="citation book cs1">Weissman, Clark (1967). <a rel="nofollow" class="external text" href="http://www.softwarepreservation.org/projects/LISP/book/Weismann_LISP1.5_Primer_1967.pdf"><i>LISP 1.5 Primer</i></a> <span class="cs1-format">(PDF)</span>. Belmont, California: Dickenson Publishing Company Inc.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=LISP+1.5+Primer&rft.place=Belmont%2C+California&rft.pub=Dickenson+Publishing+Company+Inc.&rft.date=1967&rft.aulast=Weissman&rft.aufirst=Clark&rft_id=http%3A%2F%2Fwww.softwarepreservation.org%2Fprojects%2FLISP%2Fbook%2FWeismann_LISP1.5_Primer_1967.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ALisp+%28programming+language%29" class="Z3988"></span><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r951705291"/></li></ul>
</div>
<h2><span class="mw-headline" id="External_links">External links</span></h2>
<div role="navigation" aria-labelledby="sister-projects" class="metadata plainlinks sistersitebox plainlist mbox-small" style="border:1px solid #aaa; padding:0; background:#f9f9f9;"><div style="padding: 0.75em 0; text-align: center;"><b style="display:block;">Lisp (programming language)</b>at Wikipedia's <a href="/wiki/Wikipedia:Wikimedia_sister_projects" title="Wikipedia:Wikimedia sister projects"><span id="sister-projects">sister projects</span></a></div><ul style="border-top:1px solid #aaa; padding: 0.75em 0; width:217px; margin:0 auto;"><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/27px-Wiktionary-logo-v2.svg.png" decoding="async" width="27" height="27" style="vertical-align: middle" srcset="/media/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/41px-Wiktionary-logo-v2.svg.png 1.5x, /media/wikipedia/en/thumb/0/06/Wiktionary-logo-v2.svg/54px-Wiktionary-logo-v2.svg.png 2x" data-file-width="391" data-file-height="391" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="https://en.wiktionary.org/wiki/Lisp" class="extiw" title="wikt:Lisp">Definitions</a> from Wiktionary</span>
</li><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/en/thumb/4/4a/Commons-logo.svg/20px-Commons-logo.svg.png" decoding="async" width="20" height="27" style="vertical-align: middle" srcset="/media/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png 1.5x, /media/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="/wiki/Category:Lisp_(programming_language)" class="extiw" title="c:Category:Lisp (programming language)">Media</a> from Wikimedia Commons</span>
</li><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/23px-Wikiquote-logo.svg.png" decoding="async" width="23" height="27" style="vertical-align: middle" srcset="/media/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/35px-Wikiquote-logo.svg.png 1.5x, /media/wikipedia/commons/thumb/f/fa/Wikiquote-logo.svg/46px-Wikiquote-logo.svg.png 2x" data-file-width="300" data-file-height="355" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="https://en.wikiquote.org/wiki/Lisp_programming_language" class="extiw" title="q:Lisp programming language">Quotations</a> from Wikiquote</span>
</li><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/26px-Wikisource-logo.svg.png" decoding="async" width="26" height="27" style="vertical-align: middle" srcset="/media/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/39px-Wikisource-logo.svg.png 1.5x, /media/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/51px-Wikisource-logo.svg.png 2x" data-file-width="410" data-file-height="430" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="https://en.wikisource.org/wiki/Lambda_Papers" class="extiw" title="s:Lambda Papers">Texts</a> from Wikisource</span>
</li><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/27px-Wikibooks-logo.svg.png" decoding="async" width="27" height="27" style="vertical-align: middle" srcset="/media/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/41px-Wikibooks-logo.svg.png 1.5x, /media/wikipedia/commons/thumb/f/fa/Wikibooks-logo.svg/54px-Wikibooks-logo.svg.png 2x" data-file-width="300" data-file-height="300" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="https://en.wikibooks.org/wiki/Subject:Lisp_programming_language" class="extiw" title="b:Subject:Lisp programming language">Textbooks</a> from Wikibooks</span>
</li><li style="min-height: 31px;"><span style="display: inline-block; width: 31px; line-height: 31px; vertical-align: middle; text-align: center;"><img alt="" src="/media/wikipedia/commons/thumb/1/1b/Wikiversity-logo-en.svg/27px-Wikiversity-logo-en.svg.png" decoding="async" width="27" height="24" style="vertical-align: middle" srcset="/media/wikipedia/commons/thumb/1/1b/Wikiversity-logo-en.svg/41px-Wikiversity-logo-en.svg.png 1.5x, /media/wikipedia/commons/thumb/1/1b/Wikiversity-logo-en.svg/54px-Wikiversity-logo-en.svg.png 2x" data-file-width="1000" data-file-height="900" /></span><span style="display: inline-block; margin-left: 4px; width: 182px; vertical-align: middle;"><a href="https://en.wikiversity.org/wiki/Topic:Lisp" class="extiw" title="v:Topic:Lisp">Resources</a> from Wikiversity</span>
</li></ul>
</div>
<dl><dt>History</dt></dl>
<ul><li><a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/history/lisp/lisp.html">History of Lisp</a> – <a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">John McCarthy</a>'s history of 12 February 1979</li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20050617031004/http://www8.informatik.uni-erlangen.de/html/lisp-enter.html">Lisp History</a> – Herbert Stoyan's history compiled from the documents (acknowledged by McCarthy as more complete than his own, see: <a rel="nofollow" class="external text" href="http://www-formal.stanford.edu/jmc/history/">McCarthy's history links</a>)</li>
<li><a rel="nofollow" class="external text" href="http://www.softwarepreservation.org/projects/LISP/">History of LISP at the Computer History Museum</a></li></ul>
<dl><dt>Associations and meetings</dt></dl>
<ul><li><a rel="nofollow" class="external text" href="http://www.alu.org/">Association of Lisp Users</a></li>
<li><a rel="nofollow" class="external text" href="http://www.weitz.de/eclm2013/">European Common Lisp Meeting</a></li>
<li><a rel="nofollow" class="external text" href="http://european-lisp-symposium.org/">European Lisp Symposium</a></li>
<li><a rel="nofollow" class="external text" href="http://www.international-lisp-conference.org/">International Lisp Conference</a></li></ul>
<dl><dt>Books and tutorials</dt></dl>
<ul><li><i><a rel="nofollow" class="external text" href="http://www.lisperati.com/casting.html">Casting SPELs in Lisp</a></i>, a comic-book style introductory tutorial</li>
<li><i><a rel="nofollow" class="external text" href="http://paulgraham.com/onlisptext.html">On Lisp</a></i>, a free book by <a href="/wiki/Paul_Graham_(computer_programmer)" class="mw-redirect" title="Paul Graham (computer programmer)">Paul Graham</a></li>
<li><i><a rel="nofollow" class="external text" href="http://www.gigamonkeys.com/book/">Practical Common Lisp</a></i>, freeware edition by Peter Seibel</li>
<li><a rel="nofollow" class="external text" href="http://leanpub.com/lispweb">Lisp for the web</a></li>
<li><a rel="nofollow" class="external text" href="http://landoflisp.com/">Land of Lisp</a></li>
<li><a rel="nofollow" class="external text" href="http://letoverlambda.com/">Let over Lambda</a></li></ul>
<dl><dt>Interviews</dt></dl>
<ul><li><a rel="nofollow" class="external text" href="http://purl.umn.edu/107476">Oral history interview with John McCarthy</a> at <a href="/wiki/Charles_Babbage_Institute" title="Charles Babbage Institute">Charles Babbage Institute</a>, University of Minnesota, Minneapolis. McCarthy discusses his role in the development of time-sharing at the Massachusetts Institute of Technology. He also describes his work in artificial intelligence (AI) funded by the Advanced Research Projects Agency, including logic-based AI (LISP) and robotics.</li>
<li><a rel="nofollow" class="external text" href="http://www.se-radio.net/2008/01/episode-84-dick-gabriel-on-lisp/">Interview</a> with <a href="/wiki/Richard_P._Gabriel" title="Richard P. Gabriel">Richard P. Gabriel</a> (Podcast)</li></ul>
<dl><dt>Resources</dt></dl>
<ul><li><a rel="nofollow" class="external text" href="http://www.cliki.net/">CLiki: the Common Lisp wiki</a></li>
<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160311102031/http://www.cl-user.net/asp/erw/sdataQIvH87hu8NU%24DM%3D%3D/sdataQo5Y-1Mh9urk">The Common Lisp Directory</a> (via the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>; archived from <a rel="nofollow" class="external text" href="https://web.archive.org/web/20080905110332/http://cl-user.net/">the original</a>)</li>
<li><a rel="nofollow" class="external text" href="http://www.faqs.org/faqs/lisp-faq/">Lisp FAQ Index</a></li>
<li><a rel="nofollow" class="external text" href="http://paste.lisp.org/">lisppaste</a></li>
<li><a rel="nofollow" class="external text" href="http://planet.lisp.org/">Planet Lisp</a></li>
<li><a rel="nofollow" class="external text" href="http://lispnews.wordpress.com/">Weekly Lisp News</a></li>
<li><a rel="nofollow" class="external text" href="https://curlie.org/Computers/Programming/Languages/Lisp">Lisp</a> at <a href="/wiki/Curlie" class="mw-redirect" title="Curlie">Curlie</a></li></ul>
<div role="navigation" class="navbox" aria-labelledby="Lisp_programming_language" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><a href="/wiki/Template:Lisp_programming_language" title="Template:Lisp programming language"><abbr title="View this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/w/index.php?title=Template_talk:Lisp_programming_language&action=edit&redlink=1" class="new" title="Template talk:Lisp programming language (page does not exist)"><abbr title="Discuss this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">t</abbr></a></li><li class="nv-edit"><a class="external text" href="/w/index.php?title=Template:Lisp_programming_language&action=edit"><abbr title="Edit this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">e</abbr></a></li></ul></div><div id="Lisp_programming_language" style="font-size:114%;margin:0 4em"><a class="mw-selflink selflink">Lisp programming language</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Features</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Garbage_collection_(computer_science)" title="Garbage collection (computer science)">Automatic storage management</a></li>
<li><a href="/wiki/Conditional_(computer_programming)" title="Conditional (computer programming)">Conditionals</a></li>
<li><a href="/wiki/Dynamic_typing" class="mw-redirect" title="Dynamic typing">Dynamic typing</a></li>
<li><a href="/wiki/Higher-order_function" title="Higher-order function">Higher-order functions</a></li>
<li><a href="/wiki/Linked_list" title="Linked list">Linked lists</a></li>
<li><a href="/wiki/M-expression" title="M-expression">M-expressions</a> (deprecated)</li>
<li><a href="/wiki/Read%E2%80%93eval%E2%80%93print_loop" title="Read–eval–print loop">Read–eval–print loop</a></li>
<li><a href="/wiki/Recursion_(computer_science)" title="Recursion (computer science)">Recursion</a></li>
<li><a href="/wiki/S-expression" title="S-expression">S-expressions</a></li>
<li><a href="/wiki/Self-hosting_(compilers)" title="Self-hosting (compilers)">Self-hosting</a> <a href="/wiki/Compiler" title="Compiler">compiler</a></li>
<li><a href="/wiki/Tree_data_structure" class="mw-redirect" title="Tree data structure">Tree data structures</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Object-oriented_programming" title="Object-oriented programming">Object</a> systems</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Common_Lisp_Object_System" title="Common Lisp Object System">Common Lisp Object System</a> (CLOS)</li>
<li><a href="/wiki/CommonLoops" title="CommonLoops">CommonLoops</a></li>
<li><a href="/wiki/Flavors_(programming_language)" title="Flavors (programming language)">Flavors</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Programming_language_implementation" title="Programming language implementation">Implementations</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Technical_standard" title="Technical standard">Technical<br />standard(s)</a><br />exists</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Common_Lisp" title="Common Lisp">Common<br />Lisp</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Allegro_Common_Lisp" title="Allegro Common Lisp">Allegro Common Lisp</a></li>
<li><a href="/wiki/Armed_Bear_Common_Lisp" class="mw-redirect" title="Armed Bear Common Lisp">Armed Bear Common Lisp</a> (ABCL)</li>
<li><a href="/wiki/CLISP" title="CLISP">CLISP</a></li>
<li><a href="/wiki/Clozure_CL" title="Clozure CL">Clozure CL</a></li>
<li><a href="/wiki/CMU_Common_Lisp" title="CMU Common Lisp">CMU Common Lisp</a> (CMUCL)</li>
<li><a href="/wiki/Corman_Common_Lisp" title="Corman Common Lisp">Corman Common Lisp</a></li>
<li><a href="/wiki/Embeddable_Common_Lisp" title="Embeddable Common Lisp">Embeddable Common Lisp</a> (ECL)</li>
<li><a href="/wiki/GNU_Common_Lisp" title="GNU Common Lisp">GNU Common Lisp</a> (GCL)</li>
<li><a href="/wiki/LispWorks" title="LispWorks">LispWorks</a></li>
<li><a href="/wiki/Macintosh_Common_Lisp" title="Macintosh Common Lisp">Macintosh Common Lisp</a></li>
<li><a href="/wiki/Mocl" title="Mocl">Mocl</a></li>
<li><a href="/wiki/Movitz" title="Movitz">Movitz</a></li>
<li><a href="/wiki/Poplog" title="Poplog">Poplog</a></li>
<li><a href="/wiki/Steel_Bank_Common_Lisp" title="Steel Bank Common Lisp">Steel Bank Common Lisp</a> (SBCL)</li>
<li><a href="/wiki/Genera_(operating_system)" title="Genera (operating system)">Symbolics Common Lisp</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><i><a href="/wiki/History_of_the_Scheme_programming_language" title="History of the Scheme programming language">History</a></i></li>
<li><a href="/wiki/Bigloo" title="Bigloo">Bigloo</a></li>
<li><a href="/wiki/Chez_Scheme" title="Chez Scheme">Chez Scheme</a></li>
<li><a href="/wiki/Chicken_(Scheme_implementation)" title="Chicken (Scheme implementation)">Chicken</a></li>
<li><a href="/wiki/Gambit_(scheme_implementation)" title="Gambit (scheme implementation)">Gambit</a></li>
<li><a href="/wiki/Game_Oriented_Assembly_Lisp" title="Game Oriented Assembly Lisp">Game Oriented Assembly Lisp</a> (GOAL)</li>
<li><a href="/wiki/Ikarus_(Scheme_implementation)" title="Ikarus (Scheme implementation)">Ikarus</a></li>
<li><a href="/wiki/JScheme" title="JScheme">JScheme</a></li>
<li><a href="/wiki/Kawa_(Scheme_implementation)" title="Kawa (Scheme implementation)">Kawa</a></li>
<li><a href="/wiki/Larceny_(Scheme_implementation)" title="Larceny (Scheme implementation)">Larceny</a></li>
<li><a href="/wiki/MIT/GNU_Scheme" title="MIT/GNU Scheme">MIT/GNU Scheme</a></li>
<li><a href="/wiki/MultiLisp" title="MultiLisp">MultiLisp</a></li>
<li>Pocket Scheme</li>
<li><a href="/wiki/Racket_(programming_language)" title="Racket (programming language)">Racket</a></li>
<li><a href="/wiki/RScheme" title="RScheme">RScheme</a></li>
<li><a href="/wiki/Scheme_48" title="Scheme 48">Scheme 48</a></li>
<li><a href="/wiki/SCM_(Scheme_implementation)" title="SCM (Scheme implementation)">SCM</a></li>
<li><a href="/wiki/SIOD" title="SIOD">SIOD</a></li>
<li><a href="/wiki/T_(programming_language)" title="T (programming language)">T</a></li>
<li><a href="/wiki/TinyScheme" title="TinyScheme">TinyScheme</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/ISLISP" title="ISLISP">ISLISP</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/OpenLisp" title="OpenLisp">OpenLisp</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Nonstandard</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th id="Logo" scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Logo_(programming_language)" title="Logo (programming language)">Logo</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/MSWLogo" title="MSWLogo">MSWLogo</a></li>
<li><a href="/wiki/NetLogo" title="NetLogo">NetLogo</a></li>
<li><a href="/wiki/StarLogo" title="StarLogo">StarLogo</a></li>
<li><a href="/wiki/UCBLogo" title="UCBLogo">UCBLogo</a></li></ul>
</div></td></tr></tbody></table><div>
<ul><li><a href="/wiki/Arc_(programming_language)" title="Arc (programming language)">Arc</a></li>
<li><a href="/wiki/AutoLISP" title="AutoLISP">AutoLISP</a></li>
<li><a href="/wiki/BBN_LISP" title="BBN LISP">BBN LISP</a></li>
<li><a href="/wiki/Clojure" title="Clojure">Clojure</a></li>
<li><a href="/wiki/Dylan_(programming_language)" title="Dylan (programming language)">Dylan</a> (<a href="/wiki/Apple_Dylan" title="Apple Dylan">Apple</a>, <i><a href="/wiki/History_of_the_Dylan_programming_language" title="History of the Dylan programming language">history</a></i>)</li>
<li><a href="/wiki/Emacs_Lisp" title="Emacs Lisp">Emacs Lisp</a></li>
<li><a href="/wiki/EuLisp" title="EuLisp">EuLisp</a></li>
<li><a href="/wiki/Franz_Lisp" title="Franz Lisp">Franz Lisp</a>, <a href="/wiki/PC-LISP" title="PC-LISP">PC-LISP</a></li>
<li><a href="/wiki/Hy" title="Hy">Hy</a></li>
<li><a href="/wiki/Interlisp" title="Interlisp">Interlisp</a></li>
<li><a href="/wiki/Knowledge_Engineering_Environment" title="Knowledge Engineering Environment">Knowledge Engineering Environment</a></li>
<li><a href="/wiki/*Lisp" title="*Lisp">*Lisp</a></li>
<li><a href="/wiki/LeLisp" class="mw-redirect" title="LeLisp">LeLisp</a></li>
<li><a href="/wiki/LFE_(programming_language)" title="LFE (programming language)">LFE</a></li>
<li><a href="/wiki/Lisp_Machine_Lisp" title="Lisp Machine Lisp">Lisp Machine Lisp</a></li>
<li><a href="/wiki/Maclisp" title="Maclisp">Maclisp</a></li>
<li><a href="/wiki/MDL_(programming_language)" title="MDL (programming language)">MDL</a></li>
<li><a href="/wiki/MLisp" title="MLisp">MLisp</a></li>
<li><a href="/wiki/NewLISP" title="NewLISP">newLISP</a></li>
<li><a href="/wiki/NIL_(programming_language)" title="NIL (programming language)">NIL</a></li>
<li><a href="/wiki/PC-LISP" title="PC-LISP">PC-LISP</a></li>
<li><a href="/wiki/Picolisp" class="mw-redirect" title="Picolisp">Picolisp</a></li>
<li><a href="/wiki/Portable_Standard_Lisp" title="Portable Standard Lisp">Portable Standard Lisp</a></li>
<li><a href="/wiki/RPL_(programming_language)" title="RPL (programming language)">RPL</a></li>
<li><a href="/wiki/S-1_Lisp" title="S-1 Lisp">S-1 Lisp</a></li>
<li><a href="/wiki/Cadence_SKILL" title="Cadence SKILL">SKILL</a></li>
<li><a href="/wiki/Spice_Lisp" title="Spice Lisp">Spice Lisp</a></li>
<li><a href="/wiki/Zetalisp" class="mw-redirect" title="Zetalisp">Zetalisp</a></li></ul></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Operating_system" title="Operating system">Operating system</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<li><a href="/wiki/Common_Lisp_Interface_Manager" title="Common Lisp Interface Manager">Common Lisp Interface Manager</a>, <a href="/wiki/McCLIM" title="McCLIM">McCLIM</a></li>
<li><a href="/wiki/Genera_(operating_system)" title="Genera (operating system)">Genera</a></li>
<li><a href="/wiki/Scsh" title="Scsh">Scsh</a></li>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Computer_hardware" title="Computer hardware">Hardware</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Lisp_machine" title="Lisp machine">Lisp machines</a></li>
<li><a href="/wiki/TI_Explorer" title="TI Explorer">TI Explorer</a></li>
<li><a href="/wiki/Space-cadet_keyboard" title="Space-cadet keyboard">Space-cadet keyboard</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Community of practice</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Technical standards</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Scheme_Requests_for_Implementation" title="Scheme Requests for Implementation">Scheme Requests for Implementation</a></li>
<li><a href="/wiki/Common_Lisp_HyperSpec" title="Common Lisp HyperSpec">Common Lisp HyperSpec</a></li>
<li><a href="/wiki/X3J13" title="X3J13">X3J13</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Education</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Books</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Common_Lisp_the_Language" title="Common Lisp the Language">Common Lisp the Language</a></li>
<li><a href="/wiki/How_to_Design_Programs" title="How to Design Programs">How to Design Programs</a> (HTDP)</li>
<li><a href="/wiki/On_Lisp" title="On Lisp">On Lisp</a></li>
<li><a href="/wiki/Practical_Common_Lisp" title="Practical Common Lisp">Practical Common Lisp</a></li>
<li><a href="/wiki/Structure_and_Interpretation_of_Computer_Programs" title="Structure and Interpretation of Computer Programs">Structure and Interpretation of Computer Programs</a> (SICP)</li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Curriculum</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/ProgramByDesign" title="ProgramByDesign">ProgramByDesign</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Organizations</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Business</th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Apple_Inc." title="Apple Inc.">Apple Computer</a></li>
<li><a href="/wiki/BBN_Technologies" title="BBN Technologies">Bolt, Beranek and Newman</a></li>
<li><a href="/wiki/Harlequin_(software_company)" title="Harlequin (software company)">Harlequin</a></li>
<li><a href="/wiki/Lucid_Inc." title="Lucid Inc.">Lucid Inc.</a></li>
<li><a href="/wiki/Symbolics" title="Symbolics">Symbolics</a></li>
<li><a href="/wiki/Xanalys" title="Xanalys">Xanalys</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Education</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Massachusetts_Institute_of_Technology" title="Massachusetts Institute of Technology">Massachusetts Institute of Technology</a> (MIT)</li>
<li><a href="/wiki/MIT_Computer_Science_and_Artificial_Intelligence_Laboratory" title="MIT Computer Science and Artificial Intelligence Laboratory">MIT Computer Science and Artificial Intelligence Laboratory</a> (CSAIL)</li>
<li><a href="/wiki/Stanford_University_centers_and_institutes#Stanford_Artificial_Intelligence_Laboratory" title="Stanford University centers and institutes">Stanford Artificial Intelligence Laboratory</a></li>
<li><a href="/wiki/University_of_California,_Berkeley" title="University of California, Berkeley">University of California, Berkeley</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">People</th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><td colspan="2" class="navbox-list navbox-even" style="width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Edmund_Berkeley" title="Edmund Berkeley">Edmund Berkeley</a></li>
<li><a href="/wiki/Daniel_G._Bobrow" title="Daniel G. Bobrow">Daniel G. Bobrow</a></li>
<li><a href="/wiki/William_Clinger_(computer_scientist)" title="William Clinger (computer scientist)">William Clinger</a></li>
<li><a href="/wiki/R._Kent_Dybvig" title="R. Kent Dybvig">R. Kent Dybvig</a></li>
<li><a href="/wiki/Matthias_Felleisen" title="Matthias Felleisen">Matthias Felleisen</a></li>
<li><a href="/wiki/Robert_Bruce_Findler" title="Robert Bruce Findler">Robert Bruce Findler</a></li>
<li><a href="/wiki/Matthew_Flatt" title="Matthew Flatt">Matthew Flatt</a></li>
<li><a href="/wiki/Phyllis_Fox" title="Phyllis Fox">Phyllis Fox</a></li>
<li><a href="/wiki/Paul_Graham_(programmer)" title="Paul Graham (programmer)">Paul Graham</a></li>
<li><a href="/wiki/Richard_Greenblatt_(programmer)" title="Richard Greenblatt (programmer)">Richard Greenblatt</a></li>
<li>Timothy P. Hart</li>
<li><a href="/wiki/Louis_Hodes" title="Louis Hodes">Louis Hodes</a></li>
<li>Mike Levin</li>
<li><a href="/wiki/David_Luckham" title="David Luckham">David Luckham</a></li>
<li><a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">John McCarthy</a></li>
<li><a href="/wiki/Robert_Tappan_Morris" title="Robert Tappan Morris">Robert Tappan Morris</a></li>
<li><a href="/wiki/Joel_Moses" title="Joel Moses">Joel Moses</a></li>
<li><a href="/wiki/David_Park_(computer_scientist)" title="David Park (computer scientist)">David Park</a></li>
<li><a href="/wiki/Steve_Russell_(computer_scientist)" title="Steve Russell (computer scientist)">Steve Russell</a></li>
<li><a href="/wiki/Richard_Stallman" title="Richard Stallman">Richard Stallman</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Common_Lisp" title="Common Lisp">Common Lisp</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Scott_Fahlman" title="Scott Fahlman">Scott Fahlman</a></li>
<li><a href="/wiki/Richard_P._Gabriel" title="Richard P. Gabriel">Richard P. Gabriel</a></li>
<li><a href="/wiki/Philip_Greenspun" title="Philip Greenspun">Philip Greenspun</a> (<a href="/wiki/Greenspun%27s_tenth_rule" title="Greenspun's tenth rule">10th rule</a>)</li>
<li><a href="/wiki/David_A._Moon" title="David A. Moon">David A. Moon</a></li>
<li><a href="/wiki/Kent_Pitman" title="Kent Pitman">Kent Pitman</a></li>
<li><a href="/wiki/Guy_L._Steele_Jr." title="Guy L. Steele Jr.">Guy L. Steele Jr.</a></li>
<li><a href="/wiki/Daniel_Weinreb" title="Daniel Weinreb">Daniel Weinreb</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Scheme_(programming_language)" title="Scheme (programming language)">Scheme</a></th><td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Shriram_Krishnamurthi" title="Shriram Krishnamurthi">Shriram Krishnamurthi</a></li>
<li><a href="/wiki/Guy_L._Steele_Jr." title="Guy L. Steele Jr.">Guy L. Steele Jr.</a></li>
<li><a href="/wiki/Gerald_Jay_Sussman" title="Gerald Jay Sussman">Gerald Jay Sussman</a></li>
<li><a href="/wiki/Julie_Sussman" class="mw-redirect" title="Julie Sussman">Julie Sussman</a></li></ul>
</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Logo_(programming_language)" title="Logo (programming language)">Logo</a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Hal_Abelson" title="Hal Abelson">Hal Abelson</a></li>
<li><a href="/wiki/Denison_Bollay" title="Denison Bollay">Denison Bollay</a></li>
<li><a href="/wiki/Wally_Feurzeig" title="Wally Feurzeig">Wally Feurzeig</a></li>
<li><a href="/wiki/Brian_Harvey_(lecturer)" title="Brian Harvey (lecturer)">Brian Harvey</a></li>
<li><a href="/wiki/Seymour_Papert" title="Seymour Papert">Seymour Papert</a></li>
<li><a href="/wiki/Mitchel_Resnick" title="Mitchel Resnick">Mitchel Resnick</a></li>
<li><a href="/wiki/Cynthia_Solomon" title="Cynthia Solomon">Cynthia Solomon</a></li></ul>
</div></td></tr></tbody></table><div></div></td></tr></tbody></table><div></div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>
<ul><li><img alt="Category" src="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/16px-Folder_Hexagonal_Icon.svg.png" decoding="async" title="Category" width="16" height="14" srcset="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/24px-Folder_Hexagonal_Icon.svg.png 1.5x, /media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/32px-Folder_Hexagonal_Icon.svg.png 2x" data-file-width="36" data-file-height="31" /> <b><a href="/wiki/Category:Lisp_(programming_language)" title="Category:Lisp (programming language)">Category</a></b></li>
<li><img alt="Category" src="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/16px-Folder_Hexagonal_Icon.svg.png" decoding="async" title="Category" width="16" height="14" srcset="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/24px-Folder_Hexagonal_Icon.svg.png 1.5x, /media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/32px-Folder_Hexagonal_Icon.svg.png 2x" data-file-width="36" data-file-height="31" /> <b><a href="/wiki/Category:Lisp_programming_language_family" title="Category:Lisp programming language family">Category</a></b></li>
<li><img alt="List-Class article" src="/media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" title="List-Class article" width="16" height="16" srcset="/media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, /media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <b><a href="/wiki/List_of_Lisp-family_programming_languages" title="List of Lisp-family programming languages">List</a></b></li></ul>
</div></td></tr></tbody></table></div>
<div role="navigation" class="navbox" aria-labelledby="John_McCarthy" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><a href="/wiki/Template:John_McCarthy_navbox" title="Template:John McCarthy navbox"><abbr title="View this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:John_McCarthy_navbox" title="Template talk:John McCarthy navbox"><abbr title="Discuss this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">t</abbr></a></li><li class="nv-edit"><a class="external text" href="/w/index.php?title=Template:John_McCarthy_navbox&action=edit"><abbr title="Edit this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">e</abbr></a></li></ul></div><div id="John_McCarthy" style="font-size:114%;margin:0 4em"><a href="/wiki/John_McCarthy_(computer_scientist)" title="John McCarthy (computer scientist)">John McCarthy</a></div></th></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/Artificial_intelligence" title="Artificial intelligence">Artificial intelligence</a></li>
<li><a href="/wiki/Circumscription_(logic)" title="Circumscription (logic)">Circumscription</a></li>
<li><a href="/wiki/Dartmouth_workshop" title="Dartmouth workshop">Dartmouth workshop</a></li>
<li><a href="/wiki/Frame_problem" title="Frame problem">Frame problem</a></li>
<li><a href="/wiki/Garbage_collection_(computer_science)" title="Garbage collection (computer science)">Garbage collection</a></li>
<li><a class="mw-selflink selflink">Lisp</a></li>
<li><a href="/wiki/McCarthy_Formalism" title="McCarthy Formalism">McCarthy Formalism</a></li>
<li><a href="/wiki/McCarthy_91_function" title="McCarthy 91 function">McCarthy 91 function</a></li>
<li><a href="/wiki/Situation_calculus" title="Situation calculus">Situation calculus</a></li>
<li><a href="/wiki/Space_fountain" title="Space fountain">Space fountain</a></li></ul>
</div></td></tr></tbody></table></div>
<div role="navigation" class="navbox" aria-labelledby="Programming_languages" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div class="plainlinks hlist navbar mini"><ul><li class="nv-view"><a href="/wiki/Template:Programming_languages" title="Template:Programming languages"><abbr title="View this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Programming_languages" title="Template talk:Programming languages"><abbr title="Discuss this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">t</abbr></a></li><li class="nv-edit"><a class="external text" href="/w/index.php?title=Template:Programming_languages&action=edit"><abbr title="Edit this template" style=";;background:none transparent;border:none;-moz-box-shadow:none;-webkit-box-shadow:none;box-shadow:none; padding:0;">e</abbr></a></li></ul></div><div id="Programming_languages" style="font-size:114%;margin:0 4em"><a href="/wiki/Programming_language" title="Programming language">Programming languages</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div id="*_Comparison_*_Timeline_*_History">
<ul><li><a href="/wiki/Comparison_of_programming_languages" title="Comparison of programming languages">Comparison</a></li>
<li><a href="/wiki/Timeline_of_programming_languages" title="Timeline of programming languages">Timeline</a></li>
<li><a href="/wiki/History_of_programming_languages" title="History of programming languages">History</a></li></ul>
</div></td></tr><tr><td colspan="2" class="navbox-list navbox-odd" style="width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><a href="/wiki/ALGOL" title="ALGOL">ALGOL</a></li>
<li><a href="/wiki/APL_(programming_language)" title="APL (programming language)">APL</a></li>
<li><a href="/wiki/Assembly_language" title="Assembly language">Assembly</a></li>
<li><a href="/wiki/BASIC" title="BASIC">BASIC</a></li>
<li><a href="/wiki/C_(programming_language)" title="C (programming language)">C</a></li>
<li><a href="/wiki/C%2B%2B" title="C++">C++</a></li>
<li><a href="/wiki/C_Sharp_(programming_language)" title="C Sharp (programming language)">C#</a></li>
<li><a href="/wiki/COBOL" title="COBOL">COBOL</a></li>
<li><a href="/wiki/Go_(programming_language)" title="Go (programming language)">Go</a></li>
<li><a href="/wiki/Erlang_(programming_language)" title="Erlang (programming language)">Erlang</a></li>
<li><a href="/wiki/Forth_(programming_language)" title="Forth (programming language)">Forth</a></li>
<li><a href="/wiki/Fortran" title="Fortran">Fortran</a></li>
<li><a href="/wiki/Haskell_(programming_language)" title="Haskell (programming language)">Haskell</a></li>
<li><a href="/wiki/Java_(programming_language)" title="Java (programming language)">Java</a></li>
<li><a href="/wiki/JavaScript" title="JavaScript">JavaScript</a></li>
<li><a href="/wiki/Kotlin_(programming_language)" title="Kotlin (programming language)">Kotlin</a></li>
<li><a class="mw-selflink selflink">Lisp</a></li>
<li><a href="/wiki/ML_(programming_language)" title="ML (programming language)">ML</a></li>
<li><a href="/wiki/Objective-C" title="Objective-C">Objective-C</a></li>
<li><a href="/wiki/Pascal_(programming_language)" title="Pascal (programming language)">Pascal</a></li>
<li><a href="/wiki/Perl" title="Perl">Perl</a></li>
<li><a href="/wiki/PHP" title="PHP">PHP</a></li>
<li><a href="/wiki/Prolog" title="Prolog">Prolog</a></li>
<li><a href="/wiki/Python_(programming_language)" title="Python (programming language)">Python</a></li>
<li><a href="/wiki/R_(programming_language)" title="R (programming language)">R</a></li>
<li><a href="/wiki/Ruby_(programming_language)" title="Ruby (programming language)">Ruby</a></li>
<li><a href="/wiki/Rust_(programming_language)" title="Rust (programming language)">Rust</a></li>
<li><a href="/wiki/SQL" title="SQL">SQL</a></li>
<li><a href="/wiki/Shell_script" title="Shell script">Shell</a></li>
<li><a href="/wiki/Simula" title="Simula">Simula</a></li>
<li><a href="/wiki/Smalltalk" title="Smalltalk">Smalltalk</a></li>
<li><a href="/wiki/Swift_(programming_language)" title="Swift (programming language)">Swift</a></li>
<li><i><a href="/wiki/List_of_programming_languages" title="List of programming languages">more...</a></i></li></ul>
</div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div>
<ul><li><img alt="Category" src="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/16px-Folder_Hexagonal_Icon.svg.png" decoding="async" title="Category" width="16" height="14" srcset="/media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/24px-Folder_Hexagonal_Icon.svg.png 1.5x, /media/wikipedia/en/thumb/4/48/Folder_Hexagonal_Icon.svg/32px-Folder_Hexagonal_Icon.svg.png 2x" data-file-width="36" data-file-height="31" /> <a href="/wiki/Category:Programming_languages" title="Category:Programming languages">Category</a></li>
<li><img alt="List-Class article" src="/media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" title="List-Class article" width="16" height="16" srcset="/media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, /media/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <b>Lists:</b> <a href="/wiki/List_of_programming_languages" title="List of programming languages">Alphabetical</a></li>
<li><a href="/wiki/List_of_programming_languages_by_type" title="List of programming languages by type">Categorical</a></li>
<li><a href="/wiki/Generational_list_of_programming_languages" title="Generational list of programming languages">Generational</a></li>
<li><a href="/wiki/Non-English-based_programming_languages" title="Non-English-based programming languages">Non-English-based</a></li></ul>
</div></td></tr></tbody></table></div>
<div role="navigation" class="navbox authority-control" aria-labelledby="Authority_control_frameless_&#124;text-top_&#124;10px_&#124;alt=Edit_this_at_Wikidata_&#124;link=https&#58;//www.wikidata.org/wiki/Q132874&#124;Edit_this_at_Wikidata" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th id="Authority_control_frameless_&#124;text-top_&#124;10px_&#124;alt=Edit_this_at_Wikidata_&#124;link=https&#58;//www.wikidata.org/wiki/Q132874&#124;Edit_this_at_Wikidata" scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control</a> <a href="/wiki/Q132874" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="/media/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" style="vertical-align: text-top" srcset="/media/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, /media/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></th><td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"><div style="padding:0em 0.25em">
<ul><li><span class="nowrap"><a href="/wiki/Biblioteca_Nacional_de_Espa%C3%B1a" title="Biblioteca Nacional de España">BNE</a>: <span class="uid"><a rel="nofollow" class="external text" href="http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?action=display&authority_id=XX535292">XX535292</a></span></span></li>
<li><span class="nowrap"><a href="/wiki/BNF_(identifier)" class="mw-redirect" title="BNF (identifier)">BNF</a>: <span class="uid"><a rel="nofollow" class="external text" href="https://catalogue.bnf.fr/ark:/12148/cb11934831x">cb11934831x</a> <a rel="nofollow" class="external text" href="https://data.bnf.fr/ark:/12148/cb11934831x">(data)</a></span></span></li>
<li><span class="nowrap"><a href="/wiki/GND_(identifier)" class="mw-redirect" title="GND (identifier)">GND</a>: <span class="uid"><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4035918-9">4035918-9</a></span></span></li>
<li><span class="nowrap"><a href="/wiki/LCCN_(identifier)" class="mw-redirect" title="LCCN (identifier)">LCCN</a>: <span class="uid"><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/subjects/sh85077449">sh85077449</a></span></span></li>
<li><span class="nowrap"><a href="/wiki/SUDOC_(identifier)" class="mw-redirect" title="SUDOC (identifier)">SUDOC</a>: <span class="uid"><a rel="nofollow" class="external text" href="https://www.idref.fr/027270394">027270394</a></span></span></li></ul>
</div></td></tr></tbody></table></div>
' |
Whether or not the change was made through a Tor exit node (tor_exit_node) | false |
Unix timestamp of change (timestamp) | 1595053841 |
