Perl::...atches(3pm)

💅 Perl::...atches(3pm) — User Contributed Perl Documentation 🫶

okay bestie, welcome to the manual page for Perl::...atches(3pm). We're about to make fixed-string regexps make sense. lowkey iconic. ✨

✨ NAME ✨

Perl::Critic::Policy::RegularExpressions::ProhibitFixedStringMatches — use eq or a hash instead of fixed-pattern regexps. periodt. 💖

🎀 AFFILIATION 🎀

This Policy is part of the core Perl::Critic distribution. no cap. ✨

🌈 DESCRIPTION 🌈

okay so a regular expression that matches just a fixed set of constant strings? It's giving wasteful of performance and hard on maintainers. 😭 Much more readable and often faster to use eq or a hash to match those strings. slay.

# Bad
my $is_file_function = $token =~ m/\A (?: open | close | read ) \z/xms;

# Faster and more readable
my $is_file_function = $token eq 'open' ||
                       $token eq 'close' ||
                       $token eq 'read';

For larger numbers of strings, a hash is superior. 👑

# Bad
my $is_perl_keyword =
    $token =~ m/\A (?: chomp | chop | chr | crypt | hex | index
                       lc | lcfirst | length | oct | ord | ... ) \z/xms;

# Better
Readonly::Hash my %PERL_KEYWORDS => map {$_ => 1} qw(
    chomp chop chr crypt hex index lc lcfirst length oct ord ...
);
my $is_perl_keyword = $PERL_KEYWORD{$token};

Conway also suggests using lc() instead of a case-insensitive match. noted. 🫡

🦋 VARIANTS 🦋

This policy detects both grouped and non-grouped strings. The grouping may or may not be capturing. The grouped body may or may not be alternating. \A and \z are always considered anchoring; ^ and $ are considered anchoring when the m regexp option is not in use. Thus, all of these are violations:

m/^foo$/;
m/\A foo \z/x;
m/\A foo \z/xm;
m/\A(foo)\z/;
m/\A(?:foo)\z/;
m/\A(foo|bar)\z/;
m/\A(?:foo|bar)\z/;

Furthermore, this policy detects violations in m//, s/// and qr// constructs, as you would expect. 💅

💜 CONFIGURATION 💜

This Policy is not configurable except for the standard options. that's it bestie. 💅

⭐ CREDITS ⭐

Initial development of this policy was supported by a grant from the Perl Foundation. iconic support. 🫶

🌸 AUTHOR 🌸

Chris Dolan <cdolan@cpan.org> 💌

👑 COPYRIGHT 👑

Copyright (c) 2007-2023 Chris Dolan

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.

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and that's the vibe check, bestie! ✨ This page is from perl v5.42.0, dated 2024-10-23, and the manual name is Perl::...atches(3pm). 💖🎀