NAME
    Acme::CPANModules::SmartMatch - List of modules to do smart matching

VERSION
    This document describes version 0.007 of Acme::CPANModules::SmartMatch
    (from Perl distribution Acme-CPANModules-SmartMatch), released on
    2024-07-01.

DESCRIPTION
    About smart match

    Smart matching, via the operator "~~", was introduced in perl 5.10
    (released 2007). It's inspired by Perl 6 (now called Raku)'s
    "given/when" and/or Ruby's "case" and "===" operator that can "do the
    right/smart thing" in a "case" statement. Smart matching was indeed
    introduced along the new "switch" in perl 5.10.

    What can smart match do? A whole lot. It can do string equality like
    "eq" if given a string on the left hand side and a string on the right
    hand side. Or it can do numeric equality like "==" when both sides are
    numbers. It can do regex matching like "=~" if the left hand side is a
    scalar and the right hand side is a regexp.

    But wait, there's (much) more. Interesting things begin when the
    left/right hand side is an array/hash/code/object. "$str ~~
    @ary_of_strs", probably the most common use-case for smart matching, can
    do value-in-array checking, equivalent to "grep { $str eq $_ }
    @ary_of_strs" but with short-circuiting capability. Then there's "$re ~~
    @ary_of_strs" which can perform regex matching over the elements of
    array. Now what about when the right hand side is an arrayref or
    hashref? Or the left hand side? What if the array is an array of regexes
    instead? Or a mix of other types?

    You need a full-page table as a reference of what will happen in smart
    matching, depending on the combination of operands. Things got complex
    real fast. Behaviors were changed from release to release, starting from
    5.10.1. Then nobody was sure what smart matching should or should not do
    exactly.

    In the end almost everyone agrees that smart matching is a bad fit for a
    weakly typed language like Perl. The programmer needs to be explicit on
    what type of operation should be done by specifying the appropriate
    /operator/ (e.g. "==" vs "eq") instead of the operator deducing what
    operation needs to be done depending on the operand, because in Perl the
    operand's type is unclear. Mainly, a scalar can be a string, or a
    number, or a bool, or all.

    The roadmap to removal

    In perl 5.18 (2013), 6 years after being introduced and used by
    programmers without warning, smart match was declared as experimental,
    which is weird if you think about it. You now have to add "use
    experimental "smartmatch"" to silence the warning. What happens to the
    "switch" statement then? Since it's tied to smart matching, it also gets
    the same fate: became experimental in 5.18.

    In perl 5.38 (2023) smart match is deprecated. You can no longer silence
    the warning with "use experimental 'smartmatch'" and must replace the
    use of smart match with something else.

    Perl 5.42 (planned 2025) will finally remove smart match, resulting in a
    syntax error if you still use it.

    Modules

    However, if you still miss smart matching, some modules have been
    written to give you the same/similar feature.

    match::smart (by TOBYINK, first released 2013, pure-perl) gives you a
    similar behaviour to perl's own "~~". It can be used as the "|M|"
    operator or as the match() function.

    Switch::Back (by DCONWAY, first released in June 2024, pure-perl).
    Written by one of the designers of Perl 6, Switch::Back offers roughly
    the same feature set as the old "switch" and smartmatching. Although
    there's no longer "~~", just the smartmatch() function. So basically
    what match::smart offers, but 11 years later.

    match::simple (by TOBYINK which is also the author of "match::smart",
    first released in 2013, in the same distribution as "match::smart",
    available in XS as well as pure-perl) offers a simplified version of
    smart matching. It has 8 kinds of behaviors depending only on the
    /right/ hand side.

    Also see match::simple::sugar which gives you "when", "then", and
    "numeric" for use in a for() statement as a switch/use alternative.

    Switch::Right (by DCONWAY, first released in June 2024, pure-perl). Also
    like TOBYINK with his duo of "match::smart" and "match::simple", DCONWAY
    offers a companion to "Switch::Back", a simplified/reimagined version of
    "switch" and smartmatching by simplifying the rules from 23 to just 6.
    The rules still depend on a mix of left and right operands.

    Personal take

    I personally haven't used "switch" all that much in Perl, though I used
    to use quite a bit of smartmatching in the 2010s, mostly the "$str ~~
    @ary_of_strs" variant. I won't use "match::smart" or "Switch::Back" in
    any practical code any time soon (or ever), but which between
    "match::simple" and "Switch::Right" are the best compromise? I guess
    we'll have to see. In the mean time, see my benchmark in
    Bencher::ScenarioBundle::SmartMatch.

    Other modules

    Smart::Match (by LEONT, first released in 2011, pure-perl) offers a
    bunch of functions related to matching. Probably too low-level to use if
    you just want a smart match replacement.

ACME::CPANMODULES ENTRIES
    match::smart
        Author: TOBYINK <https://metacpan.org/author/TOBYINK>

    Switch::Back
    match::simple
        Author: TOBYINK <https://metacpan.org/author/TOBYINK>

    match::simple::sugar
        Author: TOBYINK <https://metacpan.org/author/TOBYINK>

    Switch::Right
    Bencher::ScenarioBundle::SmartMatch
    Smart::Match
        Author: LEONT <https://metacpan.org/author/LEONT>

FAQ
  What is an Acme::CPANModules::* module?
    An Acme::CPANModules::* module, like this module, contains just a list
    of module names that share a common characteristics. It is a way to
    categorize modules and document CPAN. See Acme::CPANModules for more
    details.

  What are ways to use this Acme::CPANModules module?
    Aside from reading this Acme::CPANModules module's POD documentation,
    you can install all the listed modules (entries) using cpanm-cpanmodules
    script (from App::cpanm::cpanmodules distribution):

     % cpanm-cpanmodules -n SmartMatch

    Alternatively you can use the cpanmodules CLI (from App::cpanmodules
    distribution):

        % cpanmodules ls-entries SmartMatch | cpanm -n

    or Acme::CM::Get:

        % perl -MAcme::CM::Get=SmartMatch -E'say $_->{module} for @{ $LIST->{entries} }' | cpanm -n

    or directly:

        % perl -MAcme::CPANModules::SmartMatch -E'say $_->{module} for @{ $Acme::CPANModules::SmartMatch::LIST->{entries} }' | cpanm -n

    This Acme::CPANModules module also helps lcpan produce a more meaningful
    result for "lcpan related-mods" command when it comes to finding related
    modules for the modules listed in this Acme::CPANModules module. See
    App::lcpan::Cmd::related_mods for more details on how "related modules"
    are found.

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/Acme-CPANModules-SmartMatch>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-Acme-CPANModules-SmartMatch>.

SEE ALSO
    Bencher::ScenarioBundle::SmartMatch

    Acme::CPANModules - about the Acme::CPANModules namespace

    cpanmodules - CLI tool to let you browse/view the lists

AUTHOR
    perlancar <perlancar@cpan.org>

CONTRIBUTING
    To contribute, you can send patches by email/via RT, or send pull
    requests on GitHub.

    Most of the time, you don't need to build the distribution yourself. You
    can simply modify the code, then test via:

     % prove -l

    If you want to build the distribution (e.g. to try to install it locally
    on your system), you can install Dist::Zilla,
    Dist::Zilla::PluginBundle::Author::PERLANCAR,
    Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two
    other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps
    required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE
    This software is copyright (c) 2024, 2023 by perlancar
    <perlancar@cpan.org>.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=Acme-CPANModules-Smar
    tMatch>

    When submitting a bug or request, please include a test-file or a patch
    to an existing test-file that illustrates the bug or desired feature.

