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 v5.18.1                            Perl::Critic::Policy::RegularExpressions::RequireExtendedFormatting(3pm)