{ "content": [ { "type": "text", "text": "# perlexperiment (man)\n\n## NAME\n\nperlexperiment - A listing of experimental features in Perl\n\n## DESCRIPTION\n\nThis document lists the current and past experimental features in the perl core. Although all\nof these are documented with their appropriate topics, this succinct listing gives you an\noverview and basic facts about their status.\n\n## Sections\n\n- **NAME**\n- **DESCRIPTION** (3 subsections)\n- **SEE ALSO**\n- **AUTHORS**\n- **COPYRIGHT**\n- **LICENSE**\n\nUse structuredContent.sections for detailed options, examples, and full documentation.\n" } ], "structuredContent": { "command": "perlexperiment", "section": "", "mode": "man", "summary": "perlexperiment - A listing of experimental features in Perl", "synopsis": null, "tldr_summary": null, "tldr_examples": [], "tldr_source": null, "flags": [], "examples": [], "see_also": [], "section_outline": [ { "name": "NAME", "lines": 2, "subsections": [] }, { "name": "DESCRIPTION", "lines": 7, "subsections": [ { "name": "Current experiments", "lines": 140 }, { "name": "Accepted features", "lines": 107 }, { "name": "Removed features", "lines": 63 } ] }, { "name": "SEE ALSO", "lines": 2, "subsections": [] }, { "name": "AUTHORS", "lines": 4, "subsections": [] }, { "name": "COPYRIGHT", "lines": 2, "subsections": [] }, { "name": "LICENSE", "lines": 5, "subsections": [] } ], "sections": { "NAME": { "content": "perlexperiment - A listing of experimental features in Perl\n", "subsections": [] }, "DESCRIPTION": { "content": "This document lists the current and past experimental features in the perl core. Although all\nof these are documented with their appropriate topics, this succinct listing gives you an\noverview and basic facts about their status.\n\nSo far we've merely tried to find and list the experimental features and infer their\ninception, versions, etc. There's a lot of speculation here.\n", "subsections": [ { "name": "Current experiments", "content": "Smart match (\"~~\")\nIntroduced in Perl 5.10.0\n\nModified in Perl 5.10.1, 5.12.0\n\nUsing this feature triggers warnings in the category \"experimental::smartmatch\".\n\nThe ticket for this experiment is [perl #13173]\n.\n\nPluggable keywords\nIntroduced in Perl 5.11.2\n\nSee \"PLkeywordplugin\" in perlapi for the mechanism.\n\nThe ticket for this experiment is [perl #13199]\n.\n\nRegular Expression Set Operations\nIntroduced in Perl 5.18\n\nUsing this feature triggers warnings in the category \"experimental::regexsets\".\n\nThe ticket for this experiment is [perl #13197]\n.\n\nSee also: \"Extended Bracketed Character Classes\" in perlrecharclass\n\nSubroutine signatures\nIntroduced in Perl 5.20.0\n\nUsing this feature triggers warnings in the category \"experimental::signatures\".\n\nThe ticket for this experiment is [perl #13681]\n.\n\nAliasing via reference\nIntroduced in Perl 5.22.0\n\nUsing this feature triggers warnings in the category \"experimental::refaliasing\".\n\nThe ticket for this experiment is [perl #14150]\n.\n\nSee also: \"Assigning to References\" in perlref\n\nThe \"const\" attribute\nIntroduced in Perl 5.22.0\n\nUsing this feature triggers warnings in the category \"experimental::constattr\".\n\nThe ticket for this experiment is [perl #14428]\n.\n\nSee also: \"Constant Functions\" in perlsub\n\nuse re 'strict';\nIntroduced in Perl 5.22.0\n\nUsing this feature triggers warnings in the category \"experimental::restrict\".\n\nThe ticket for this experiment is [perl #18755]\n\n\nSee \"'strict' mode\" in re\n\nThe <:win32> IO pseudolayer\nUsing this feature triggers warnings in the category \"experimental::win32perlio\".\n\nThe ticket for this experiment is [perl #13198]\n.\n\nSee also \"PERLIO\" in perlrun\n\nDeclaring a reference to a variable\nIntroduced in Perl 5.26.0\n\nUsing this feature triggers warnings in the category \"experimental::declaredrefs\".\n\nThe ticket for this experiment is [perl #15458]\n.\n\nSee also: \"Declaring a Reference to a Variable\" in perlref\n\nThere is an \"installhtml\" target in the Makefile.\nThe ticket for this experiment is [perl #12726]\n.\n\n(Limited) Variable-length look-behind\nIntroduced in Perl 5.30.0.\n\nVariability of up to 255 characters is handled.\n\nUsing this feature triggers warnings in the category \"experimental::vlb\".\n\nThe ticket for this experiment is [perl #18756]\n.\n\nSee also: \"(*positivelookbehind:pattern)\" in perlre and\n\"(*negativelookbehind:pattern)\" in perlre\n\nUnicode private use character hooks\nIntroduced in Perl 5.30.0.\n\nThis feature is part of an interface intended for internal and experimental use by\nthe perl5 developers. You are unlikely to encounter it in the wild.\n\nUsing this feature triggers warnings in the category \"experimental::privateuse\".\n\nThe ticket for this experiment is [perl #18758]\n.\n\nUnicode property wildcards\nIntroduced in Perl 5.30.0.\n\nThis feature allows regular expression matching against Unicode character properties\nto be expressed more concisely.\n\nUsing this feature triggers warnings in the category\n\"experimental::unipropwildcards\".\n\nThe ticket for this experiment is [perl #18759]\n.\n\nisa infix operator\nIntroduced in Perl 5.32.0.\n\nUsing this feature triggers warnings in the category \"experimental::isa\".\n\nThe ticket for this experiment is [perl #18754]\n\n\ntry/catch control structure\nIntroduced in Perl 5.34.0.\n\nUsing this feature triggers warnings in the category \"experimental::try\".\n\nThe ticket for this experiment is [perl #18760]\n\n" }, { "name": "Accepted features", "content": "These features were so wildly successful and played so well with others that we decided to\nremove their experimental status and admit them as full, stable features in the world of\nPerl, lavishing all the benefits and luxuries thereof. They are also awarded +5 Stability\nand +3 Charisma.\n\n64-bit support\nIntroduced in Perl 5.005\n\ndie accepts a reference\nIntroduced in Perl 5.005\n\nDB module\nIntroduced in Perl 5.6.0\n\nSee also perldebug, perldebtut\n\nWeak references\nIntroduced in Perl 5.6.0\n\nInternal file glob\nIntroduced in Perl 5.6.0\n\nfork() emulation\nIntroduced in Perl 5.6.1\n\nSee also perlfork\n\n-Dusemultiplicity -Duseithreads\nIntroduced in Perl 5.6.0\n\nAccepted in Perl 5.8.0\n\nSupport for long doubles\nIntroduced in Perl 5.6.0\n\nAccepted in Perl 5.8.1\n\nThe \"\\N\" regex character class\nThe \"\\N\" character class, not to be confused with the named character sequence\n\"\\N{NAME}\", denotes any non-newline character in a regular expression.\n\nIntroduced in Perl 5.12\n\nExact version of acceptance unclear, but no later than Perl 5.18.\n\n\"(?{code})\" and \"(??{ code })\"\nIntroduced in Perl 5.6.0\n\nAccepted in Perl 5.20.0\n\nSee also perlre\n\nLinux abstract Unix domain sockets\nIntroduced in Perl 5.9.2\n\nAccepted before Perl 5.20.0. The Socket library is now primarily maintained on CPAN,\nrather than in the perl core.\n\nSee also Socket\n\nLvalue subroutines\nIntroduced in Perl 5.6.0\n\nAccepted in Perl 5.20.0\n\nSee also perlsub\n\nBacktracking control verbs\n\"(*ACCEPT)\"\n\nIntroduced in Perl 5.10\n\nAccepted in Perl 5.20.0\n\nThe <:pop> IO pseudolayer\nSee also \"PERLIO\" in perlrun\n\nAccepted in Perl 5.20.0\n\n\"\\s\" in regexp matches vertical tab\nAccepted in Perl 5.22.0\n\nPostfix dereference syntax\nIntroduced in Perl 5.20.0\n\nAccepted in Perl 5.24.0\n\nLexical subroutines\nIntroduced in Perl 5.18.0\n\nAccepted in Perl 5.26.0\n\nString- and number-specific bitwise operators\nIntroduced in Perl 5.22.0\n\nAccepted in Perl 5.28.0\n\nAlphabetic assertions\nIntroduced in Perl 5.28.0\n\nAccepted in Perl 5.32.0\n\nScript runs\nIntroduced in Perl 5.28.0\n\nAccepted in Perl 5.32.0\n" }, { "name": "Removed features", "content": "These features are no longer considered experimental and their functionality has disappeared.\nIt's your own fault if you wrote production programs using these features after we explicitly\ntold you not to (see perlpolicy).\n\n5.005-style threading\nIntroduced in Perl 5.005\n\nRemoved in Perl 5.10\n\nperlcc Introduced in Perl 5.005\n\nMoved from Perl 5.9.0 to CPAN\n\nThe pseudo-hash data type\nIntroduced in Perl 5.6.0\n\nRemoved in Perl 5.9.0\n\nGetOpt::Long Options can now take multiple values at once (experimental)\n\"Getopt::Long\" upgraded to version 2.35\n\nRemoved in Perl 5.8.8\n\nAssertions\nThe \"-A\" command line switch\n\nIntroduced in Perl 5.9.0\n\nRemoved in Perl 5.9.5\n\nTest::Harness::Straps\nMoved from Perl 5.10.1 to CPAN\n\n\"legacy\"\nThe experimental \"legacy\" pragma was swallowed by the \"feature\" pragma.\n\nIntroduced in Perl 5.11.2\n\nRemoved in Perl 5.11.3\n\nLexical $\nUsing this feature triggered warnings in the category \"experimental::lexicaltopic\".\n\nIntroduced in Perl 5.10.0\n\nRemoved in Perl 5.24.0\n\nArray and hash container functions accept references\nUsing this feature triggered warnings in the category \"experimental::autoderef\".\n\nSuperseded by \"Postfix dereference syntax\".\n\nIntroduced in Perl 5.14.0\n\nRemoved in Perl 5.24.0\n\n\"our\" can have an experimental optional attribute \"unique\"\nIntroduced in Perl 5.8.0\n\nDeprecated in Perl 5.10.0\n\nRemoved in Perl 5.28.0\n" } ] }, "SEE ALSO": { "content": "For a complete list of features check feature.\n", "subsections": [] }, "AUTHORS": { "content": "brian d foy \"\"\n\nSébastien Aperghis-Tramoni \"\"\n", "subsections": [] }, "COPYRIGHT": { "content": "Copyright 2010, brian d foy \"\"\n", "subsections": [] }, "LICENSE": { "content": "You can use and redistribute this document under the same terms as Perl itself.\n\n\n\nperl v5.34.0 2025-07-25 PERLEXPERIMENT(1)", "subsections": [] } } } }