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 v5.18.1     Perl::Critic::Policy::ValuesAndExpressions::ProhibitInterpolationOfLiterals(3pm)