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.