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#      $URL: http://perlcritic.tigris.org/svn/perlcritic/trunk/Perl-Critic/lib/Perl/Critic/Theme.pm $
#     $Date: 2008-05-17 20:03:55 -0500 (Sat, 17 May 2008) $
#   $Author: clonezone $
# $Revision: 2349 $
##############################################################################
package Perl::Critic::Theme;
use strict;
use warnings;
use English qw(-no_match_vars);
use Readonly;
use base qw{ Exporter };
use List::MoreUtils qw(any);
use Perl::Critic::Utils qw{ :characters :data_conversion };
use Perl::Critic::Exception::Fatal::Internal qw{ &throw_internal };
use Perl::Critic::Exception::Configuration::Option::Global::ParameterValue
    qw{ &throw_global_value };
#-----------------------------------------------------------------------------
our $VERSION = '1.083_003';
#-----------------------------------------------------------------------------
Readonly::Array our @EXPORT_OK => qw{
    $RULE_INVALID_CHARACTER_REGEX
    cook_rule
};
#-----------------------------------------------------------------------------
Readonly::Scalar our $RULE_INVALID_CHARACTER_REGEX =>
    qr/ ( [^()\s\w\d+\-*&|!] ) /xms;
#-----------------------------------------------------------------------------
Readonly::Scalar my $CONFIG_KEY => 'theme';
#-----------------------------------------------------------------------------
sub new {
    my ( $class, %args ) = @_;
    my $self = bless {}, $class;
    $self->_init( %args );
    return $self;
}
#-----------------------------------------------------------------------------
sub _init {
    my ($self, %args) = @_;
    my $rule = $args{-rule} || $EMPTY;
    if ( $rule =~ m/$RULE_INVALID_CHARACTER_REGEX/xms ) {
        throw_global_value
            option_name     => $CONFIG_KEY,
            option_value    => $rule,
            message_suffix => qq{contains an invalid character: "$1".};
    }
    $self->{_rule} = cook_rule( $rule );
    return $self;
}
#-----------------------------------------------------------------------------
sub rule {
    my $self = shift;
    return $self->{_rule};
}
#-----------------------------------------------------------------------------
sub policy_is_thematic {
    my ($self, %args) = @_;
    my $policy = $args{-policy}
        || throw_internal 'The -policy argument is required';
    ref $policy
        || throw_internal 'The -policy must be an object';
    my $rule = $self->{_rule} or return 1;
    my %themes = hashify( $policy->get_themes() );
    # This bit of magic turns the rule into a perl expression that can be
    # eval-ed for truth.  Each theme name in the rule is translated to 1 or 0
    # if the $policy belongs in that theme.  For example:
    #
    # 'bugs && (pbp || core)'  ...could become... '1 && (0 || 1)'
    my $as_code = $rule; #Making a copy, so $rule is preserved
    $as_code =~ s/ ( [\w\d]+ ) /exists $themes{$1} || 0/gemx;
    my $is_thematic = eval $as_code;  ## no critic (ProhibitStringyEval)
    if ($EVAL_ERROR) {
        throw_global_value
            option_name     => $CONFIG_KEY,
            option_value    => $rule,
            message_suffix  => q{contains a syntax error.};
    }
    return $is_thematic;
}
#-----------------------------------------------------------------------------
sub cook_rule {
    my ($raw_rule) = @_;
    return if not defined $raw_rule;
    #Translate logical operators
    $raw_rule =~ s{\b not \b}{!}ixmg;     # "not" -> "!"
    $raw_rule =~ s{\b and \b}{&&}ixmg;    # "and" -> "&&"
    $raw_rule =~ s{\b or  \b}{||}ixmg;    # "or"  -> "||"
    #Translate algebra operators (for backward compatibility)
    $raw_rule =~ s{\A [-] }{!}ixmg;     # "-" -> "!"     e.g. difference
    $raw_rule =~ s{   [-] }{&& !}ixmg;  # "-" -> "&& !"  e.g. difference
    $raw_rule =~ s{   [*] }{&&}ixmg;    # "*" -> "&&"    e.g. intersection
    $raw_rule =~ s{   [+] }{||}ixmg;    # "+" -> "||"    e.g. union
    my $cooked_rule = lc $raw_rule;  #Is now cooked!
    return $cooked_rule;
}
1;
__END__
#-----------------------------------------------------------------------------
HideShow 94 lines of Pod
=pod
=head1 NAME
Perl::Critic::Theme - Construct thematic sets of policies.
=head1 DESCRIPTION
This is a helper class for evaluating theme expressions into sets of Policy
objects.  There are no user-serviceable parts here.
=head1 METHODS
=over
=item C<< new( -rule => $rule_expression ) >>
Returns a reference to a new Perl::Critic::Theme object.  C<-rule> is a string
expression that evaluates to true or false for each Policy.. See L<"THEME
RULES"> for more information.
=item C<< policy_is_thematic( -policy => $policy ) >>
Given a reference to a L<Perl::Critic::Policy> object, this method returns
evaluates the rule against the themes that are associated with the Policy.
Returns 1 if the Policy satisfies the rule, 0 otherwise.
=item C< rule() >
Returns the rule expression that was used to construct this Theme.  The rule
may have been translated into a normalized expression.  See L<"THEME RULES">
for more information.
=back
=head2 THEME RULES
A theme rule is a simple boolean expression, where the operands are the names
of any of the themes associated with the Perl::Critic::Polices.
Theme names can be combined with logical operators to form arbitrarily complex
expressions.  Precedence is the same as normal mathematics, but you can use
parentheses to enforce precedence as well.  Supported operators are:
   Operator    Altertative    Example
   ----------------------------------------------------------------------------
   &&          and            'pbp && core'
   ||          or             'pbp || (bugs && security)'
   !           not            'pbp && ! (portability || complexity)
See L<Perl::Critic/"CONFIGURATION"> for more information about customizing the
themes for each Policy.
=head1 SUBROUTINES
=over
=item C<cook_rule( $rule )>
Standardize a rule into a almost executable Perl code.  The "almost" comes
from the fact that theme names are left as is.
=back
=head1 CONSTANTS
=over
=item C<$RULE_INVALID_CHARACTER_REGEX>
A regular expression that will return the first character in the matched
expression that is not valid in a rule.
=back
=head1 AUTHOR
Jeffrey Thalhammer  <thaljef@cpan.org>
=head1 COPYRIGHT
Copyright (c) 2006-2008 Jeffrey Thalhammer
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
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