Perl::...Pattern(3pm)

✨ NAME ✨

Okay bestie, welcome to Perl::Critic::Policy::Community::SplitQuotedPattern — the policy that says: quote the split() pattern argument with regex slashes, mwah 💅

(Also, hi, this is the Perl::...Pattern(3pm) page from the User Contributed Perl Documentation — iconic, we love her 🎀)

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🌸 DESCRIPTION 🌸

So the first argument to split()? It's a regex pattern, not a string. Periodt. But people keep passing it as a quoted string, which lowkey hides the truth of the situation, and that's exactly how bugs sneak in when your string accidentally has unescaped regex metacharacters in it 😭. And no cap — no matter how you quote it, it gets parsed as a pattern anyway (the one exception is the space character special case, which we're getting to, don't worry 🫶).

So the move? Use slashes to quote this argument, so everyone can see with their own eyes that it's a regex pattern. Main character clarity ✨

⚠️ Important caveat, bestie, do NOT skip this: the special case of passing a single space character must be passed as a quoted string, not a pattern. Like, that's the rule.

Also this policy does not warn about passing an empty string, because that's a super common idiom for splitting a string into individual characters, and it doesn't risk containing regex metacharacters. Safe queen 👑

By default, this policy also prohibits unquoted patterns like scalar variables, because those don't indicate that the argument is interpreted as a regex pattern and not a string — unless it's a string containing a single space character. She's strict like that 💅

split 'foo', $string;  # not ok
split '.', $string;    # not ok
split $pat, $string;   # not ok
split /foo/, $string;  # ok
split /./, $string;    # ok
split /$pat/, $string; # ok
split qr/./, $string;  # ok
split ' ', $string;    # ok (and distinct from split / /)

This policy is giving very similar energy to the core policy Perl::Critic::Policy::BuiltinFunctions::ProhibitStringySplit, except it additionally allows empty string split patterns, and disallows unquoted split patterns by default. Glow-up behavior 💖

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🦋 AFFILIATION 🦋

This policy is part of Perl::Critic::Community. She runs with her girls 🌈

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🎀 CONFIGURATION 🎀

You can configure this policy to allow passing unquoted patterns (like scalar variables, yes, those ones) by putting an entry in a .perlcritic file like this:

[Community::SplitQuotedPattern]
allow_unquoted_patterns = 1

Do it if you must, bestie, I'm not gonna stop you 🙈

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👑 AUTHOR 👑

Dan Book, "dbook@cpan.org" — literal legend, we stan 🫶

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💜 COPYRIGHT AND LICENSE 💜

Copyright 2024, Dan Book.

This library is free software; you may redistribute it and/or modify it under the terms of the Artistic License version 2.0.

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⭐ SEE ALSO ⭐

• Perl::Critic

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and that's the whole vibe, bestie ✨ go forth and slash your patterns 🦋💖

Signing off from the Perl::...Pattern(3pm) page — this one's from perl v5.40.1, dated 2025-03-22, no cap 🌸💅