NAME

       Perl::Critic::Policy::RegularExpressions::RequireExtendedFormatting - Always use the "/x"
       modifier with regular expressions.

AFFILIATION

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

DESCRIPTION

       Extended regular expression formatting allows you mix whitespace and comments into the
       pattern, thus making them much more readable.

           # Match a single-quoted string efficiently...

           m{'[^\\']*(?:\\.[^\\']*)*'};  #Huh?

           # Same thing with extended format...

           m{
               '           # an opening single quote
               [^\\']      # any non-special chars (i.e. not backslash or single quote)
               (?:         # then all of...
                   \\ .    #    any explicitly backslashed char
                   [^\\']* #    followed by an non-special chars
               )*          # ...repeated zero or more times
               '           # a closing single quote
           }x;

CONFIGURATION

       You might find that putting a "/x" on short regular expressions to be excessive.  An
       exception can be made for them by setting "minimum_regex_length_to_complain_about" to the
       minimum match length you'll allow without a "/x".  The length only counts the regular
       expression, not the braces or operators.

           [RegularExpressions::RequireExtendedFormatting]
           minimum_regex_length_to_complain_about = 5

           $num =~ m<(\d+)>;              # ok, only 5 characters
           $num =~ m<\d\.(\d+)>;          # not ok, 9 characters

       This option defaults to 0.

       Because using "/x" on a regex which has whitespace in it can make it harder to read (you
       have to escape all that innocent whitespace), by default, you can have a regular
       expression that only contains whitespace and word characters without the modifier.  If you
       want to restrict this, turn on the "strict" option.

           [RegularExpressions::RequireExtendedFormatting]
           strict = 1

           $string =~ m/Basset hounds got long ears/;  # no longer ok

       This option defaults to false.

NOTES

       For common regular expressions like e-mail addresses, phone numbers, dates, etc., have a
       look at the Regexp::Common module.  Also, be cautions about slapping modifier flags onto
       existing regular expressions, as they can drastically alter their meaning.  See
       <http://www.perlmonks.org/?node_id=484238> for an interesting discussion on the effects of
       blindly modifying regular expression flags.

TO DO

       Add an exemption for regular expressions that contain "\Q" at the front and don't use "\E"
       until the very end, if at all.

AUTHOR

       Jeffrey Ryan Thalhammer  <jeff@imaginative-software.com>

COPYRIGHT

       Copyright (c) 2005-2011 Imaginative Software Systems. 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.

perl v5.20.2             Perl::Critic::Policy::RegularExpressions::RequireExtendedFormatting(3pm)