Covariance and contravariance (computer science): Revision history

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curprev 20:0220:02, 28 March 2025 Chriswjohnson talk contribs 54,195 bytes +36 Reworded the second paragraph, because the first sentence's structure, built around "how … relates to …", breaks its definition into separated halves, and readers must infer (due to the vagueness of "how") what type of thing "variance" might be. The next two sentences, both rhetorical questions, are converted to a single sentence of statements. NOTE: This edit would be significantly improved by enumerating variance types in sentence 1, and stating their effects on the examples in sentence 2. undo

curprev 14:3714:37, 18 March 2025 W.andrea talk contribs 54,159 bytes −31 →top: The lead doesn't need to be rewritten IMO. There are some things that could be improved, I suppose, but nothing major. Please be more specific if needed. undo
curprev 14:2414:24, 18 March 2025 W.andrea talk contribs m 54,190 bytes +38 →Contravariant method parameter type: +links undo
curprev 07:4307:43, 18 March 2025 180.150.37.222 talk 54,152 bytes +31 Lead does not seem to match wiki guidelines undo Tag: Visual edit

curprev 01:3701:37, 2 March 2025 Rusty Cat talk contribs 54,121 bytes −1 →Covariant arrays in Java and C#: extra space undo
curprev 01:3601:36, 2 March 2025 Rusty Cat talk contribs 54,122 bytes +19 →Covariant arrays in Java and C#: reword comment undo

curprev 12:5812:58, 20 November 2024 W.andrea talk contribs m 54,103 bytes +2 rv grammar regressions undo
curprev 06:5306:53, 20 November 2024 TocaTheFrog talk contribs m 54,101 bytes −3 Grammar and punctuation fixes undo Tags: Visual edit Newcomer task Newcomer task: references

curprev 00:4600:46, 28 June 2024 Citation bot talk contribs 54,104 bytes −22 Removed parameters. | Use this bot. Report bugs. | Suggested by Abductive | #UCB_webform 2175/3850 undo

curprev 14:4514:45, 22 June 2024 W.andrea talk contribs 54,126 bytes +35 →Summary of variance and inheritance: no citations undo
curprev 12:4612:46, 22 June 2024 212.92.201.134 talk 54,091 bytes −40 I was deleting Scala from the table "The following table summarizes the rules for overriding methods in the languages discussed above." As far as I know, Scala non-generic (concrete) parameters have no contravariance, and no covariance either (except return type). Scala supports contravariance (and covariance) with generic parameters (in generic classes and generic methods) and with abstract types (for example: type T <: A). undo

curprev 21:4221:42, 23 December 2023 W.andrea talk contribs 54,131 bytes +4 Undid revision 1191354127 by DuncanSungWKim (talk). Cf. verbiage at Function (mathematics). undo Tag: Undo
curprev 01:0501:05, 23 December 2023 DuncanSungWKim talk contribs m 54,127 bytes −4 No edit summary undo Tags: Reverted Visual edit: Switched

curprev 11:3511:35, 11 September 2023 180.233.127.65 talk 54,131 bytes +35 →Summary of variance and inheritance: Made table layout more logical undo Tags: Mobile edit Mobile web edit

curprev 06:4506:45, 13 August 2023 209.203.60.197 talk 54,096 bytes 0 →Formal definition undo

curprev 16:0316:03, 10 August 2023 Kali the ilo talk contribs m 54,096 bytes 0 OCaml does not permit types to be capitalized. undo

curprev 01:0701:07, 16 July 2023 Jlwoodwa talk contribs m 54,096 bytes +11 upd link undo

curprev 21:0921:09, 11 July 2023 Vilhelm.s talk contribs 54,085 bytes −5 →C# examples: "fatal" could be either a run-time or compile-time error undo
curprev 20:5520:55, 11 July 2023 Vilhelm.s talk contribs 54,090 bytes −273 this paragraph was just wrong undo

curprev 19:2419:24, 22 June 2023 W.andrea talk contribs 54,363 bytes +275 →top: WP:REFERS. Bold "Invariant". Add a bunch of links. Grammar. undo
curprev 03:3303:33, 22 June 2023 Cngzz1 talk contribs 54,088 bytes +338 Add in-line citation and information undo

curprev 13:1413:14, 17 June 2023 Citation bot talk contribs 53,750 bytes +20 Add: date. | Use this bot. Report bugs. | Suggested by Headbomb | Linked from Wikipedia:WikiProject_Academic_Journals/Journals_cited_by_Wikipedia/Sandbox2 | #UCB_webform_linked 193/999 undo

curprev 17:4117:41, 3 June 2023 WikiCleanerBot talk contribs m 53,730 bytes 0 v2.05b - Bot T20 CW#61 - Fix errors for CW project (Reference before punctuation) undo Tag: WPCleaner

curprev 02:3102:31, 30 May 2023 W.andrea talk contribs 53,730 bytes −1,204 Remove duplicate citations. undo
curprev 02:0802:08, 30 May 2023 Cngzz1 talk contribs 54,934 bytes +1,602 Remove duplicate references, use {{rp}} instead. Fixed citation formatting and added author name. Added more inline citations. undo

curprev 20:1720:17, 29 May 2023 W.andrea talk contribs 53,332 bytes −170 →C# examples: Remove duplicate references, use {{rp}} instead. undo
curprev 07:4307:43, 29 May 2023 Cngzz1 talk contribs m 53,502 bytes +354 Add reference for for C#. undo

curprev 13:5713:57, 30 April 2023 MichaelMaggs talk contribs 53,148 bytes +51 Adding local short description: "Programming language concept", overriding Wikidata description "subtyping property of a generic type in a programming language" undo Tag: Shortdesc helper

curprev 21:3521:35, 1 April 2023 73.223.72.200 talk 53,097 bytes +141 →Formal definition: Resolve clarification needed by switching to same notation used in body. Also add sentence to explicitly define the notation. undo Tag: nowiki added

curprev 20:5920:59, 22 March 2023 Liquidev talk contribs 52,956 bytes −170 Remove poorly worded and misguiding sentence about using `dynamic` in C# to circumvent static typing and work around variance undo Tag: Visual edit: Switched

curprev 21:5621:56, 8 March 2023 184.151.246.79 talk 53,126 bytes +1 typo and redundant link undo

curprev 21:4421:44, 5 November 2022 Citation bot talk contribs 53,125 bytes +24 Add: s2cid, authors 1-1. Removed parameters. Some additions/deletions were parameter name changes. | Use this bot. Report bugs. | Suggested by Abductive | #UCB_webform 2715/3850 undo

curprev 18:1018:10, 17 October 2022 W.andrea talk contribs 53,101 bytes +21 →top: Move latest addition to the correct spot. undo
curprev 16:4916:49, 17 October 2022 2601:180:200:cb3:2ded:5260:ac5c:88f6 talk 53,080 bytes +252 Adds concise definition undo Tag: Visual edit

curprev 15:1515:15, 19 September 2022 Pelirodri1248 talk contribs m 52,828 bytes +1 No edit summary undo

curprev 11:1811:18, 6 May 2022 DerSpezialist talk contribs m 52,827 bytes −1 →Covariant method parameter type: Remove space between references undo

curprev 11:4911:49, 14 February 2022 84.213.205.150 talk 52,828 bytes +45 →Inheritance in object-oriented languages: added more helpful description to align with the terminology used in the rest of the text undo
curprev 11:4811:48, 14 February 2022 84.213.205.150 talk 52,783 bytes +32 →Inheritance in object-oriented languages: Added helpful description, to avoid having to look up UML. undo

curprev 17:4417:44, 20 January 2022 Iridescent 2 talk contribs m 52,751 bytes 0 →Data: Cleanup and typo fixing, typo(s) fixed: similarly- → similarly undo Tag: AWB

curprev 04:0404:04, 17 December 2021 RnTkm talk contribs 52,751 bytes −167 Undid revision 1054485302 by RnTkm (talk). withdraw undo Tag: Undo

curprev 19:0319:03, 24 November 2021 100.33.242.54 talk 52,918 bytes +1 →Function types: Fixed unmatched parentheses undo

curprev 08:5008:50, 10 November 2021 RnTkm talk contribs 52,917 bytes +167 →Inheritance in object-oriented languages: +{{Dubious}} "invariance" undo Tag: Reverted

curprev 03:4403:44, 3 November 2021 RnTkm talk contribs 52,750 bytes +53 →Formal definition: {{More citations needed section}} undo

curprev 09:4509:45, 1 November 2021 2a02:8108:96c0:781c:795f:655f:cfe7:621e talk 52,697 bytes +51 Giving an example of a language that supports contravariance in parameter types undo

curprev 16:1216:12, 10 October 2021 2a02:810a:8d00:1298:b0ba:f2ae:b358:e1d talk 52,646 bytes −2 →Formal definition undo
curprev 16:1116:11, 10 October 2021 2a02:810a:8d00:1298:b0ba:f2ae:b358:e1d talk 52,648 bytes 0 →Formal definition undo
curprev 16:1016:10, 10 October 2021 2a02:810a:8d00:1298:b0ba:f2ae:b358:e1d talk 52,648 bytes +127 →Formal definition: Explicitly stated formal definition, reformulated bivariance undo Tags: nowiki added Visual edit

curprev 11:3311:33, 7 October 2021 RDBrown talk contribs 52,521 bytes +369 →Cite book, tweak cites undo
curprev 07:0907:09, 7 October 2021 Linneris talk contribs 52,152 bytes +57 clarification needed undo

curprev 05:2105:21, 7 August 2021 Ovenliners talk contribs 52,095 bytes +150 Corrected statement that C# does not support covariant return types - it does as of C# 9.0. undo

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