/ 
Perl-Critic-Bangs-1.11_02
River stage two • 8 direct dependents • 13 total dependents
/ Perl::Critic::Policy::Bangs::ProhibitUselessTopic

NAME

Perl::Critic::Policy::Bangs::ProhibitUselessTopic - Explicitly checking a regex against $_ is unnecessary

AFFILIATION

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

DESCRIPTION

Match or substitution operations are performed against variables, such as:

$x =~ /foo/;
$x =~ s/foo/bar/;
$x =~ tr/a-mn-z/n-za-m/;

If a variable is not specified, the match is against $_, also known as "the topic".

# These are identical.
/foo/;
$_ =~ /foo/;

# These are identical.
s/foo/bar/;
$_ =~ s/foo/bar/;

# These are identical.
tr/a-mn-z/n-za-m/;
$_ =~ tr/a-mn-z/n-za-m/;

Including the $_ =~ is unnecessary, adds complexity, and is not idiomatic Perl.

Another place that $_ is unnecessary is with a filetest operator.

# These are identical.
my $size = -s $_;
my $size = -s;

# These are identical.
if ( -r $_ ) { ...
if ( -r ) { ...

CONFIGURATION

This Policy is not configurable except for the standard options.

TO DO

I hope to expand this to other places that $_ is not needed, like in a call to split or a million other functions where $_ is assumed.

AUTHOR

Andy Lester <andy@petdance.com>

COPYRIGHT

Copyright (c) 2013 Andy Lester <andy@petdance.com>

This library is free software; you can redistribute it and/or modify it under the terms of the Artistic License 2.0.