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Perl::Critic::Policy::ValuesAndExpressions::ProhibitMismatchedOperators

NAME

Perl::Critic::Policy::ValuesAndExpressions::ProhibitMismatchedOperators - Don’t mix numeric operators with string operands, or vice-versa.

AFFILIATION

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

DESCRIPTION

Using the wrong operator type for a value can obscure coding intent and possibly lead to subtle errors. An example of this is mixing a string equality operator with a numeric value, or vice-versa.

if ($foo == 'bar') {} #not ok
if ($foo eq 'bar') {} #ok
if ($foo eq 123) {} #not ok
if ($foo == 123) {} #ok

CONFIGURATION

This Policy is not configurable except for the standard options.

NOTES

If warnings are enabled, the Perl interpreter usually warns you about using mismatched operators at run-time. This Policy does essentially the same thing, but at author-time. That way, you can find out about them sooner.

Perl handles the strings ’NaN’ and ’inf’ as special numbers and creates an NV struct when compared with a numeric operator. Although not necessary it is allowed to write code such as:
my $i = ’inf’+0; This pattern helps others understand that the variable is indeed the Infinite or NaN numbers as Perl interprets them. Only these two special string numbers are allowed to have the ’+’ operator which would otherwise be allowed only for strings.

AUTHOR

Peter Guzis <pguzis AT cpan DOT org>

COPYRIGHT

Copyright (c) 2006-2023 Peter Guzis. All rights reserved.

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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