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share/PerlCritic/Critic/Policy/Variables/ProhibitPunctuationVars.pm  view on Meta::CPAN

our $VERSION = '1.108';

#-----------------------------------------------------------------------------

Readonly::Scalar my $DESC => q<Magic punctuation variable used>;
Readonly::Scalar my $EXPL => [79];

#-----------------------------------------------------------------------------

# There is no English.pm equivalent for $].
sub supported_parameters {
    return (
        {
            name           => 'allow',
            description    => 'The additional variables to allow.',
            default_string => $EMPTY,
            behavior       => 'string list',
            list_always_present_values =>
                [ qw< $_ @_ $1 $2 $3 $4 $5 $6 $7 $8 $9 _ $] > ],
        },
        {
            name               => 'string_mode',
            description        =>
                'Controls checking interpolated strings for punctuation variables.',
            default_string     => 'thorough',
            behavior           => 'enumeration',
            enumeration_values => [ qw< simple disable thorough > ],
            enumeration_allow_multiple_values => 0,
        },
    );
}

sub default_severity { return $SEVERITY_LOW }
sub default_themes   { return qw< core pbp cosmetic > }

sub applies_to {
    return qw<
        PPI::Token::Magic
        PPI::Token::Quote::Double
        PPI::Token::Quote::Interpolate
        PPI::Token::QuoteLike::Command
        PPI::Token::QuoteLike::Backtick
        PPI::Token::QuoteLike::Regexp
        PPI::Token::QuoteLike::Readline
        PPI::Token::HereDoc
    >;
}

#-----------------------------------------------------------------------------


# This list matches the initialization of %PPI::Token::Magic::magic.
## no critic (ValuesAndExpressions::RequireInterpolationOfMetachars)
Readonly::Array my @MAGIC_VARIABLES =>
    qw{
        $1 $2 $3 $4 $5 $6 $7 $8 $9
        $_ $& $` $' $+ @+ %+ $* $. $/ $|
        $\\ $" $; $% $= $- @- %- $)
        $~ $^ $: $? $! %! $@ $$ $< $>
        $( $0 $[ $] @_ @*

        $^L $^A $^E $^C $^D $^F $^H
        $^I $^M $^N $^O $^P $^R $^S
        $^T $^V $^W $^X %^H

        $::|
    },
    q<$}>,
    q<$,>,
    q<$#>,
    q<$#+>,
    q<$#->;
## use critic

# The main regular expression for detecting magic variables.
Readonly::Scalar my $MAGIC_REGEX => _create_magic_detector();

# The magic vars in this array will be ignored in interpolated strings
# in simple mode. See CONFIGURATION in the pod.
Readonly::Array my @IGNORE_FOR_INTERPOLATION =>
    ( q{$'}, q{$$}, q{$#}, q{$:}, );    ## no critic ( RequireInterpolationOfMetachars, ProhibitQuotedWordLists )

#-----------------------------------------------------------------------------

sub violates {
    my ( $self, $elem, undef ) = @_;

    if ( $elem->isa('PPI::Token::Magic') ) {
        return _violates_magic( $self, $elem );
    }
    elsif ( $elem->isa('PPI::Token::HereDoc') ) {
        return _violates_heredoc( $self, $elem );
    }

    #the remaining applies_to() classes are all interpolated strings
    return _violates_string( $self, $elem );
}

#-----------------------------------------------------------------------------

# Helper functions for the three types of violations: code, quotes, heredoc

sub _violates_magic {
    my ( $self, $elem, undef ) = @_;

    if ( !exists $self->{_allow}->{$elem} ) {
        return $self->violation( $DESC, $EXPL, $elem );
    }

    return;    # no violation
}

sub _violates_string {
    my ( $self, $elem, undef ) = @_;

    # RT #55604: Variables::ProhibitPunctuationVars gives false-positive on
    # qr// regexp's ending in '$'
    # We want to analyze the content of the string in the dictionary sense of
    # the word 'content'. We can not simply use the PPI content() method to
    # get this, because content() includes the delimiters.