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package Perl::Critic::Policy::Modules::RequireNoMatchVarsWithUseEnglish;
use 5.010001;
use strict;
use warnings;
use Readonly;
use Perl::Critic::Utils qw< :characters :severities >;
use parent 'Perl::Critic::Policy';
our $VERSION = '1.156';
#-----------------------------------------------------------------------------
Readonly::Scalar my $EXPL =>
q{"use English" without the '-no_match_vars' argument degrades performance.'};
Readonly::Scalar my $DESC => q{"use English" without '-no_match_vars' argument};
#-----------------------------------------------------------------------------
sub supported_parameters { return () }
sub default_severity { return $SEVERITY_LOW }
sub default_themes { return qw( core performance ) }
sub applies_to { return 'PPI::Statement::Include' }
#-----------------------------------------------------------------------------
sub violates {
my ( $self, $elem, undef ) = @_;
# "require"ing English is kind of useless.
return if $elem->type() ne 'use';
return if $elem->module() ne 'English';
my @elements = $elem->schildren();
shift @elements; # dump "use"
shift @elements; # dump "English"
if (not @elements) {
return $self->violation($DESC, $EXPL, $elem);
}
_skip_version_number( \@elements );
@elements = _descend_into_parenthesized_list_if_present(@elements);
if (not @elements) {
return $self->violation($DESC, $EXPL, $elem);
}
my $current_element = $elements[0];
while ( $current_element ) {
if ( $current_element->isa('PPI::Token::Quote') ) {
return if $current_element->string() eq '-no_match_vars';
}
elsif ( $current_element->isa('PPI::Token::QuoteLike::Words') ) {
return if $current_element->content() =~ m/-no_match_vars \b/xms;
}
elsif (
not $current_element->isa('PPI::Token::Operator')
or $current_element->content() ne $COMMA
and $current_element->content() ne $FATCOMMA
) {
return $self->violation($DESC, $EXPL, $elem);
}
shift @elements;
$current_element = $elements[0];
}
return $self->violation($DESC, $EXPL, $elem);
}
sub _skip_version_number {
my ($elements_ref) = @_;
my $current_element = $elements_ref->[0];
if ( $current_element->isa('PPI::Token::Number') ) {
shift @{$elements_ref};
}
elsif (
@{$elements_ref} >= 2
and $current_element->isa('PPI::Token::Word')
and $current_element->content() =~ m/\A v \d+ \z/xms
and $elements_ref->[1]->isa('PPI::Token::Number')
) {
# The above messy conditional necessary due to PPI not handling
# v-strings.
shift @{$elements_ref};
shift @{$elements_ref};
}
return;
}
sub _descend_into_parenthesized_list_if_present {
my @elements = @_;
return if not @elements;
my $current_element = $elements[0];
if ( $current_element->isa('PPI::Structure::List') ) {
my @grand_children = $current_element->schildren();
if (not @grand_children) {
return;
}
my $grand_child = $grand_children[0];
if ( $grand_child->isa('PPI::Statement::Expression') ) {
my @great_grand_children = $grand_child->schildren();
if (not @great_grand_children) {
return;
}
return @great_grand_children;
}
else {
return @grand_children;
}
}
return @elements;
}
1;
__END__
#-----------------------------------------------------------------------------
=pod
=head1 NAME
Perl::Critic::Policy::Modules::RequireNoMatchVarsWithUseEnglish - C<use English> must be passed a C<-no_match_vars> argument.
=head1 AFFILIATION
This Policy is part of the core L<Perl::Critic|Perl::Critic>
distribution.
=head1 DESCRIPTION
Due to unfortunate history, if you use the L<English|English> module
but don't pass in a C<-no_match_vars> argument, all regular
expressions in the entire program, not merely the module in question,
suffer a significant performance penalty, even if you only import a
subset of the variables.
use English; # not ok
use English '-no_match_vars'; # ok
use English qw< $ERRNO -no_match_vars >; # ok
use English qw($OS_ERROR); # not ok
In the last example above, while the match variables aren't loaded
into your namespace, they are still created in the C<English>
namespace and you still pay the cost.
=head1 CONFIGURATION
This Policy is not configurable except for the standard options.
=head1 AUTHOR
Elliot Shank C<< <perl@galumph.com> >>
=head1 COPYRIGHT
Copyright (c) 2008-2011 Elliot Shank.
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.
=cut
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# fill-column: 78
# indent-tabs-mode: nil
# c-indentation-style: bsd
# End:
# ex: set ts=8 sts=4 sw=4 tw=78 ft=perl expandtab shiftround :
|
