View source for Simons' BASIC

{{Infobox software
| name                   = Simons' BASIC
| logo                   = Simon's Basic Cartridge Logo.svg
| logo alt               = 
| screenshot             = Simons Basic Splash Screen.gif<!-- Image name is enough -->
| caption                = BASIC program memory is reduced by the 8 [[kilobyte|KB]] used by the cartridge.
| screenshot alt         = BASIC program memory is reduced by the 8 [[kilobyte|KB]] used by the cartridge.
| collapsible            = 
| author                 = David Simons
| developer              = [[Commodore International|Commodore]]
| released               = {{Start date and age|1983}}
| discontinued           = 
| latest release version = 
| latest release date    = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| latest preview version = 
| latest preview date    = <!-- {{Start date and age|YYYY|MM|DD|df=yes/no}} -->
| status                 = 
| operating system       = [[Commodore 64]]
| platform               = 
| size                   = 
| language               = 
| language count         = <!-- Number only -->
| language footnote      = 
| genre                  = [[BASIC extension|Extension]]
| license                = 
| alexa                  = 
| website                = <!--{{URL|example.org}}-->
| standard               = 
| AsOf                   = 
}}
'''Simons' BASIC''' <ref>{{Cite book |last=Dillon |first=Roberto |url=https://books.google.se/books?id=ecuoBQAAQBAJ&pg=PA26&dq=Simons'+BASIC+Commodore+64&hl=en&newbks=1&newbks_redir=0&source=gb_mobile_search&ovdme=1&sa=X&ved=2ahUKEwiS45v1iJaNAxX0AxAIHf6OHvIQ6AF6BAgGEAM#v=onepage&q=Simons'%20BASIC%20Commodore%2064&f=false |title=Ready: A Commodore 64 Retrospective |date=2014-12-03 |publisher=Springer |isbn=978-981-287-341-5 |pages=25 |language=en}}</ref>is an [[BASIC extension|extension]] to [[Commodore BASIC|BASIC 2.0]] for the [[Commodore 64]] home computer. Written by [[British people|British]] programmer David Simons in 1983, who was 16 years old at the time, it was distributed by [[Commodore International|Commodore]] as a [[ROM cartridge#software|cartridge]].

It is widely, but incorrectly, called "'''Simon's BASIC'''", because of confusion between the first name "Simon" and the [[surname]] "Simons".

[[File:Simons Basic.jpg|thumb|Manual front page]]
[[File:Simons BASIC Modul Hires.JPG|thumb|right|Simons' BASIC cartridge]]
[[File:Simon's BASIC cartridge.jpg|thumb|Cartridge with the misspelled label contributing to the software's naming confusion.]]

== Features ==

Simons' BASIC added an array of features to Commodore BASIC 2.0:<ref>Simons' Basic User Manual (published by Commodore)</ref>
* 114 additional [[Keyword (computing)|keywords]]
* commands to ease the coding of [[Sprite (computer science)|sprites]]
* commands to ease the coding of high-resolution and multicolor [[2D computer graphics|graphics]]
* commands to ease the coding of [[Sound chip|sound]]
* commands to aid in [[structured programming]]
* keywords to assist in writing and editing BASIC programs, similar to those in the [[VIC-20]] Programmer's Aid cartridge

Programs written in Simons' BASIC could employ [[hexadecimal]] numbers in assignments and calculations by including a {{code|$}} prefix, or [[Binary numeral system|binary]] numbers by utilizing a {{code|%}} prefix.

Because a portion of the cartridge data is [[Memory-mapped I/O|mapped]] into memory at addresses {{mono|$8000–$9FFF}}, which overlaps part of the standard C64 BASIC [[Random access memory|RAM]], the amount of available memory for BASIC programs was {{val|8|ul=KB}} less than that of a standard C64 configuration.

An extension was written by Simons and released by Commodore on [[floppy disk]] and tape as Simons' Basic Extension. This software is also known as Simons' Basic 2. It could not be released on cartridge because the original Simons' Basic cartridge had to be present in order to use the extension. Simons' Basic Extension adds another 91 commands including the much-coveted {{mono|RENUMBER}} command which renumbers the destinations of {{mono|GOTO}} and {{mono|GOSUB}} statements.<ref>Simons' Basic 2 User Manual (published by Commodore)</ref>

== The 114 keywords ==

=== Sprite (MOB) handling keywords ===
* <kbd>MOB SET</kbd> – enables a sprite and defines its attributes
* <kbd>MMOB</kbd> – positions a sprite on the screen
* <kbd>RLOCMOB</kbd> – causes a sprite to smoothly move from one location to another
* <kbd>CMOB</kbd> – sets up the two global colors for multicolor sprites
* <kbd>MOB OFF</kbd> – disables a sprite
* <kbd>DETECT</kbd> – initializes sprite collision detection
* <kbd>CHECK</kbd> – checks for a sprite collision

=== High resolution graphics handling keywords ===
* <kbd>HIRES</kbd> – initializes a high-resolution graphics mode
* <kbd>MULTI</kbd> – initializes a multicolor graphics mode
* <kbd>NRM</kbd> – returns to the text display
* <kbd>LOW COL</kbd> – changes the plotting colors
* <kbd>HI COL</kbd> – returns to the original plotting colors
* <kbd>PLOT</kbd> – draws a pixel
* <kbd>LINE</kbd> – draws a line
* <kbd>CIRCLE</kbd> – draws a circle
* <kbd>ARC</kbd> – draws an arc
* <kbd>ANGL</kbd> – draws the radius of a circle
* <kbd>PAINT</kbd> – performs a flood fill
* <kbd>REC</kbd> – draws a hollow rectangle
* <kbd>BLOCK</kbd> – draws a solid rectangle
* <kbd>DRAW</kbd> – draws a user-defined set of lines
* <kbd>ROT</kbd> – sets scaling factors for <kbd>DRAW</kbd>
* <kbd>CHAR</kbd> – plots a text character on a high-resolution screen
* <kbd>TEXT</kbd> – plots a text string on a high-resolution screen
* <kbd>TEST</kbd> – determines whether a pixel is plotted or empty

=== Other graphics handling keywords ===
* <kbd>COLOUR</kbd> – sets the background and border colors; the British spelling is used
* <kbd>CSET</kbd> – selects a character set
* <kbd>MEM</kbd> – copies character ROM to RAM
* <kbd>BCKGNDS</kbd> – configures extended background color mode
* <kbd>FLASH</kbd> – sets up a screen color to flash
* <kbd>OFF</kbd> – cancels a previous <kbd>FLASH</kbd> directive
* <kbd>BFLASH</kbd> – causes the screen border to flash
* <kbd>FCHR</kbd> – fills an area of the text screen with a given character code
* <kbd>FCOL</kbd> – changes character colors for a selected area of the screen
* <kbd>FILL</kbd> – a combination of <kbd>FCHR</kbd> and <kbd>FCOL</kbd>
* <kbd>MOVE</kbd> – copies a section of the screen
* <kbd>INV</kbd> – displays a screen area in reverse
* <kbd>LEFT</kbd> – scrolls the screen left
* <kbd>RIGHT</kbd> – scrolls the screen right
* <kbd>UP</kbd> – scrolls the screen up
* <kbd>DOWN</kbd> – scrolls the screen down
* <kbd>GRAPHICS</kbd> – reserved variable that always equals $D000 (the [[MOS Technology VIC-II|VIC-II]] chip's base address)
* <kbd>SCRSV</kbd> – saves a text screen to tape or disk
* <kbd>SCRLD</kbd> – loads a text screen from tape or disk

=== Sound handling keywords ===
* <kbd>MUSIC</kbd> – plays a series of notes based on the contents of a string variable
* <kbd>PLAY</kbd> – determines whether the program continues to run during <kbd>MUSIC</kbd>
* <kbd>VOL</kbd> – specifies the master sound volume
* <kbd>WAVE</kbd> – specifies a voice type
* <kbd>ENVELOPE</kbd> – sets [[ADSR envelope|ADSR]] parameters for a [[MOS Technology SID|SID]] voice
* <kbd>SOUND</kbd> – reserved variable that always equals $D400 (the SID chip's base address)

=== Keyboard input handling keywords ===
* <kbd>FETCH</kbd> – takes user input with restrictions defined by the command
* <kbd>INKEY</kbd> – checks for a function key press
* <kbd>ON KEY</kbd> – checks for a given keypress, then performs a branch if present
* <kbd>DISABLE</kbd> – disables the previous <kbd>ON KEY</kbd> directive
* <kbd>RESUME</kbd> – reenables the previous <kbd>ON KEY</kbd> directive

=== Input peripheral handling keywords ===
* <kbd>JOY</kbd> – reads a [[joystick]]
* <kbd>POT</kbd> – reads a [[Paddle (game controller)|paddle]]
* <kbd>PENX</kbd> – reads the [[light pen]]'s [[Horizontal plane|horizontal]] position
* <kbd>PENY</kbd> – reads the light pen's vertical position

=== Sprite/custom character definition keywords ===
* <kbd>@</kbd> – describes one line in a sprite or custom character graphic
* <kbd>DESIGN</kbd> – uses neighbouring <kbd>@</kbd> lines to define a sprite or custom character

=== Error trapping keywords ===
* <kbd>ON ERROR</kbd> – sets up a routine to trap error conditions
* <kbd>OUT</kbd> – ends an error handling routine
* <kbd>NO ERROR</kbd> – cancels <kbd>ON ERROR</kbd> and restores normal BASIC error handling

=== Disk handling keywords ===
* <kbd>DIR</kbd> – displays the disk directory without destroying the BASIC program in memory (Drive #8 only)
* <kbd>DISK</kbd> – sends a string to the disk drive's command channel (Drive #8 only)

=== Printer handling keywords ===
* <kbd>HRDCPY</kbd> – sends the text screen to the [[Printer (computing)|printer]]
* <kbd>COPY</kbd> – sends the high-resolution screen to the printer

=== String manipulation keywords ===
* <kbd>INSERT</kbd> – inserts one string into the middle of another (Note: There is no dollar sign after <kbd>INSERT</kbd>, unlike other string operators such as <kbd>STR$</kbd>, <kbd>LEFT$</kbd>, <kbd>RIGHT$</kbd>, etc.)
* <kbd>INST</kbd> – similar to <kbd>INSERT</kbd>, but overwrites rather than inserting. (Note: As with <kbd>INSERT</kbd>, there is no dollar sign after <kbd>INST</kbd>.)
* <kbd>PLACE</kbd> – searches for one string in the middle of another
* <kbd>DUP</kbd> – duplicates a character string a given number of times. (Note: As with <kbd>INSERT</kbd>, there is no dollar sign after <kbd>DUP</kbd>.)

=== Text formatting keywords ===
* <kbd>PRINT AT</kbd> – prints a string at a given screen location
* <kbd>CENTRE</kbd> – centers a character string on the screen; the British spelling is used
* <kbd>USE</kbd> – formats numeric data in strings based on a template, just like <kbd>PRINT USING</kbd> on other advanced versions of BASIC on other computers, e.g. the [[Commodore 128]], for example.
* <kbd>LIN</kbd> – returns the vertical position of the cursor

=== Maths keywords ===
Note: These operations are restricted to values that fit into a 16-bit unsigned integer, instead of the full floating-point range used by the built-in BASIC arithmetic operations and functions.
* <kbd>MOD</kbd> – performs a division operation and returns the remainder
* <kbd>DIV</kbd> – performs a division operation and returns the integer quotient
* <kbd>FRAC</kbd> – isolates the fractional portion of a number
* <kbd>EXOR</kbd> – performs an exclusive-OR logical operation

=== Programmer's aid keywords ===
* <kbd>AUTO</kbd> – automatically generates line numbers as a BASIC program is entered
* <kbd>RENUMBER</kbd> – renumbers a BASIC program (but does not fix <kbd>[[GOTO]]</kbd>/<kbd>[[GOSUB]]</kbd> statements.)
* <kbd>OLD</kbd> – undeletes a program accidentally removed by the <kbd>NEW</kbd> command
* <kbd>KEY</kbd> – assigns a string as a [[Macro (computer science)|macro]] to a [[function key]]
* <kbd>DISPLAY</kbd> – displays all function key macros
* <kbd>MERGE</kbd> – merges a BASIC program from tape or disk into the program currently in memory
* <kbd>PAGE</kbd> – displays a BASIC program listing in page format
* <kbd>OPTION</kbd> – highlights ''Simons' BASIC'' keywords when using the <kbd>LIST</kbd> command
* <kbd>DELAY</kbd> – varies the rate at which the <kbd>LIST</kbd> command scrolls the screen
* <kbd>FIND</kbd> – searches the program for a string
* <kbd>TRACE</kbd> – displays the line numbers as a program is running
* <kbd>RETRACE</kbd> – displays results of a trace
* <kbd>DUMP</kbd> – displays all variable values except for arrays
* <kbd>COLD</kbd> – resets the C64

=== Security-related keywords ===
* <kbd>DISAPA</kbd> – marks a BASIC program line for hiding
* <kbd>SECURE</kbd> – hides all lines marked with <kbd>DISAPA</kbd> so that they cannot be viewed with <kbd>LIST</kbd>

=== Structured programming keywords ===
* <kbd>ELSE</kbd> – allows an alternative branch for <kbd>IF</kbd>/<kbd>THEN</kbd> conditionals
* <kbd>REPEAT</kbd> – start of a <kbd>REPEAT</kbd>/<kbd>UNTIL</kbd> loop structure
* <kbd>UNTIL</kbd> – defines the loop condition for a <kbd>REPEAT</kbd>/<kbd>UNTIL</kbd> loop structure, and marks its end
* <kbd>RCOMP</kbd> – reinstates the most recently used <kbd>IF</kbd>/<kbd>THEN</kbd>/<kbd>ELSE</kbd> conditional
* <kbd>LOOP</kbd> – defines the start of a loop that will run until an <kbd>EXIT IF</kbd> conditional is true
* <kbd>EXIT IF</kbd> – the conditional is true, so it exits the current <kbd>LOOP</kbd>/<kbd>END LOOP</kbd> structure
* <kbd>END LOOP</kbd> – defines the end of a loop that will run until an <kbd>EXIT IF</kbd> conditional is true
* <kbd>PROC</kbd> – defines the start of a named subroutine
* <kbd>END PROC</kbd> – defines the end of a named subroutine
* <kbd>CALL</kbd> – jump to a named subroutine defined with <kbd>PROC</kbd>/<kbd>END PROC</kbd>, and stay there
* <kbd>EXEC</kbd> – call a named subroutine defined with <kbd>PROC</kbd>/<kbd>END PROC</kbd>, then return
* <kbd>LOCAL</kbd> – redefines variables for use in structures
* <kbd>GLOBAL</kbd> – reverses the effects of a previous <kbd>LOCAL</kbd> command

=== Miscellaneous keywords ===
* <kbd>CGOTO</kbd> – equivalent to <kbd>GOTO</kbd>, but accepts calculated expressions
* <kbd>RESET</kbd> – moves the <kbd>DATA</kbd> pointer to a given line number
* <kbd>PAUSE</kbd> – pauses program execution for a specified number of seconds

=== Other ===
* <kbd>$</kbd> and <kbd>%</kbd> are also considered keywords, for a total of 114.

=== Trivia ===
The band [[Barcelona (band)|Barcelona]] titled their 1999 debut album ''Simon Basic'' in tribute. The album includes the song "C-64".

== Reception ==
''[[Creative Computing]]'' stated that Simons' BASIC "almost makes the 64 into a new computer. (Probably the one it should have been in the first place.)" It praised the "very fine manual" as a contrast to Commodore's usually poor documentation, and predicted that it would become "the standard language for programming the machine … Commodore had better be planning to manufacture lots of copies because they will go fast".<ref name="onosko198311">{{cite news | url=http://www.atarimagazines.com/creative/v9n11/60_Simons_Basic.php | title=Simons' Basic. | work=Creative Computing | date=November 1983 | access-date=27 June 2014 | author=Onosko, Tim | pages=60}}</ref> ''[[Ahoy!]]'' wrote "If you do any programming in BASIC and should happen to see this product on a dealer's shelf, do not ask any questions—do not hesitate—just buy it!" The magazine praised Simons' BASIC's power and "excellent manual", and stated that "its price makes it one of the biggest bargains available for the Commodore 64".<ref name="kevelson198402">{{cite news | url=https://archive.org/stream/Ahoy_Issue_02_1984-02_Ion_International_US#page/n55/mode/2up | title=Simons' BASIC | work=Ahoy! | date=February 1984 | access-date=27 June 2014 | author=Kevelson, Morton A. | pages=57–58 }}</ref> ''[[RUN (magazine)|RUN]]''{{'}}s review was less favorable, stating that its "many powerful and useful commands … were, unfortunately, implemented very poorly for a commercial package. There is very little command parameter checking, and many things have been overlooked or ignored."<ref name="baker198504">{{cite news | url=https://archive.org/stream/run-magazine-16/Run_Issue_16_1985_Apr#page/n95/mode/2up | title=A Review of Simons' Basic | work=RUN | date=April 1985 | access-date=27 June 2014 | author=Baker, Robert W. | pages=94–95}}</ref>

The original SIMONS' BASIC cartridge (without the extension) has no provisions for reading the error channel on the [[Commodore 1541]] and [[Commodore 1571]] disk drives, nor can it perform a DIRectory listing of files or issue a DISK command on any disk drive other than Drive #8 when more than one disk drive is connected to the Commodore 64. And while most "standard" BASIC 2.0 keywords can be abbreviated by typing the first or first and second letters and then holding down the SHIFT key while typing the second (or third) letter after that, all SIMONS' BASIC keywords must be completely spelled out in full exactly as shown in the accompanying user's manual. This includes the commands COLOUR (which selects the background color and exterior border color), and CENTRE (which prints text message that are "centered" on the screen), both of which are spelled as in British English and are incorporated that way into SIMONS' BASIC.

== References ==

{{reflist}}

== External links ==
* [https://archive.org/details/SimonsBASIC Simons' Basic User Guide] on Internet Archive by David Simons, Commodore Computers, 1983. Downloadable as PDF.
* [http://retrocomputing.altervista.org/scansioni/scansioni.html Simons' Basic Italian Reference Guide] by David Simons, Commodore Editor, 1983.
* [http://www.lemon64.com/forum/viewtopic.php?t=31356&postdays=0&postorder=asc&start=0 Lemon64 Forum topic] with some informal information from David Simons himself.

{{BASIC}}

[[Category:1983 software]]
[[Category:Commodore 64 software]]
[[Category:BASIC extensions]]
[[Category:CBM software]]