🌻 📖 Perl::Critic::Policy::Plicease::ProhibitUnicodeDigitInRegexp


Perl::Critic::Policy::Plicease::ProhibitUnicodeDigitInRegexp - Prohibit non-ASCII \d in regular expressions


version 0.04


The character class \d in a regular expression matches all unicode digit character, which might not be what you expect if you are testing if a string can be used as a number in Perl. Instead use either [0-9], or if you are on Perl 5.14 or better you can use the /a modifier. This policy allows \d in expressions with an explicit /u modifier (normally on by default), as it indicates that the code is expecting Unicode semantics, including Unicode digits.

 /\d/;      # not ok
 /\d/a;     # ok
 /\d/u;     # ok
 /[0-9]/;   # ok




This policy is not configurable except for the standard options.


This is not a general policy, and should not be applied toward all applications without some thought. This is frequently true for Perl::Critic policies, but especially so for this policy.

In the general the ability to match against unicode digits is a useful ability, and doesn't constitute bad code. On the other hand, some applications don't ever need to match non-ASCII digit characters, and incorrectly rely on \d to validate as a number as Perl understands it (and Perl understands non-ASCII digits as zero regardless of what they mean in their respective languages).

This policy doesn't take into account using the re pragma.

 use re '/a';
 /\d/;  # (still) not ok


Author: Graham Ollis <plicease@cpan.org>


Ville Skyttä (SCOP)


This software is copyright (c) 2019 by Graham Ollis.

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