File Coverage

blib/lib/PPIx/Regexp/Token/Delimiter.pm

Criterion	Covered	Total	%
statement	25	25	100.0
branch	4	4	100.0
condition			n/a
subroutine	9	9	100.0
pod	3	3	100.0
total	41	41	100.0

=head1 NAME

PPIx::Regexp::Token::Delimiter - Represent the delimiters of the regular expression

=head1 SYNOPSIS

 use PPIx::Regexp::Dumper;
 PPIx::Regexp::Dumper->new( 'qr{foo}smx' )
     ->print();

=head1 INHERITANCE

C is a
L.

C has no descendants.

=head1 DESCRIPTION

This token represents the delimiters of the regular expression. Since
the tokenizer has to figure out where these are anyway, this class is
used to give the lexer a hint about what is going on.

=head1 METHODS

This class provides no public methods beyond those provided by its
superclass.

=cut

package PPIx::Regexp::Token::Delimiter;

use strict;
use warnings;

use base qw{ PPIx::Regexp::Token::Structure };

use PPIx::Regexp::Constant qw{ MINIMUM_PERL @CARP_NOT };

our $VERSION = '0.087_01';

# Return true if the token can be quantified, and false otherwise
# sub can_be_quantified { return };

sub explain {
    return 'Regular expression or replacement string delimiter';
}

=head2 perl_version_introduced

Experimentation with weird delimiters shows that they did not actually
work until Perl 5.8.3, so we return C<'5.008003'> for such delimiters.

=cut

sub perl_version_introduced {
    my ( $self ) = @_;
    $self->content() =~ m/ \A [[:^ascii:]] \z /smx
	and return '5.008003';
    return MINIMUM_PERL;
}

=head2 perl_version_removed

Perl 5.29.0 made fatal the use of non-standalone graphemes as regular
expression delimiters. Because non-characters and permanently unassigned
code points are still allowed per F, I take this to
mean characters that match C (i.e. combining diacritical
marks).  But this regular expression does not compile under Perl 5.6.

So:

This method returns C<'5.029'> for such delimiters B the
requisite regular expression compiles. Otherwise it return C.

=cut

# Perl 5.29.0 disallows unassigned code points and combining code points
# as delimiters. Unfortunately for me non-characters and illegal
# characters are explicitly allowed. Still more unfortunately, these
# match /\p{Unassigned}/. So before I match a deprecated characer, I
# have to assert that the character is neither a non-character
# (\p{Noncharacter_code_point}) nor an illegal Unicode character
# (\P{Any}).
use constant WEIRD_CHAR_RE => eval ## no critic (ProhibitStringyEval,RequireCheckingReturnValueOfEval)
'qr<
    (?! [\p{Noncharacter_code_point}\P{Any}] )
    [\p{Unassigned}\p{Mark}]
>smx';

sub perl_version_removed {
    my ( $self ) = @_;
    WEIRD_CHAR_RE
	and $self->content() =~ WEIRD_CHAR_RE
	and return '5.029';
    # I respectfully disagree with Perl Best Practices on the
    # following. When this method is called in list context it MUST
    # return undef if that's the right answer, NOT an empty list.
    # Otherwise hash constructors have the wrong number of elements.
    return undef;	## no critic (ProhibitExplicitReturnUndef)
}

1;

__END__