---
name: "Perl::Critic::Policy::RegularExpressions::ProhibitSingleCharAlternation"
section: "3pm"
platform: "linux"
package: "perl-perl-critic"
version: "1.156-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Perl::Critic::Policy::RegularExpressions::ProhibitSingleCharAlternation"
---

# Perl::Critic::Policy::RegularExpressions::ProhibitSingleCharAlternation(3pm)

Use "\[abc\]" instead of "a\|b\|c".

## NAME

Perl::Critic::Policy::RegularExpressions::ProhibitSingleCharAlternation - Use "\[abc\]" instead of "a\|b\|c".

## AFFILIATION

This Policy is part of the core Perl::Critic distribution.

## DESCRIPTION

Character classes (like `"[abc]"`) are significantly faster than single character alternations (like `"(?:a|b|c)"`).  This policy complains if you have more than one instance of a single character in an alternation.  So `"(?:a|the)"` is allowed, but `"(?:a|e|i|o|u)"` is not.

## CONFIGURATION

This Policy is not configurable except for the standard options.

## CREDITS

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

## 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