NAME

       Perl::Critic::Policy::ValuesAndExpressions::ProhibitInterpolationOfLiterals - Always use single quotes
       for literal strings.

AFFILIATION

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

DESCRIPTION

       Don't use double-quotes or "qq//" if your string doesn't require interpolation.  This saves the
       interpreter a bit of work and it lets the reader know that you really did intend the string to be
       literal.

           print "foobar";     #not ok
           print 'foobar';     #ok
           print qq/foobar/;   #not ok
           print q/foobar/;    #ok

           print "$foobar";    #ok
           print "foobar\n";   #ok
           print qq/$foobar/;  #ok
           print qq/foobar\n/; #ok

           print qq{$foobar};  #preferred
           print qq{foobar\n}; #preferred

       Use of double-quotes might be reasonable if the string contains single quote (') characters:

           print "it's me";    # ok, if configuration flag set

CONFIGURATION

       The types of quoting styles to exempt from this policy can be configured via the "allow" option.  This
       must be a whitespace-delimited combination of some or all of the following styles: "qq{}", "qq()",
       "qq[]", and "qq//".

       This is useful because some folks have configured their editor to apply special syntax highlighting
       within certain styles of quotes.  For example, you can tweak "vim" to use SQL highlighting for everything
       that appears within "qq{}" or "qq[]" quotes.  But if those strings are literal, Perl::Critic will
       complain.  To prevent this, put the following in your .perlcriticrc file:

           [ValuesAndExpressions::ProhibitInterpolationOfLiterals]
           allow = qq{} qq[]

       The flag "allow_if_string_contains_single_quote" permits double-quoted strings if the string contains a
       single quote (') character.  It defaults to off; to turn it on put the following in your .perlcriticrc
       file:

           [ValuesAndExpressions::ProhibitInterpolationOfLiterals]
           allow_if_string_contains_single_quote = 1

SEE ALSO

       Perl::Critic::Policy::ValuesAndExpressions::RequireInterpolationOfMetachars

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 v5.32.1                    Perl::Critic::Policy::ValuesAndExpressions::ProhibitInterpolationOfLiterals(3pm)