PPIx::Regexp::Token::MUseriContributed Perl DoPPIx::Regexp::Token::Modifier(3)NAMEPPIx::Regexp::Token::Modifier - Represent modifiers.
SYNOPSIS
use PPIx::Regexp::Dumper;
PPIx::Regexp::Dumper->new( 'qr{foo}smx' )
->print();
The trailing "smx" will be represented by this class.
This class also represents the whole of things like "(?ismx)". But the
modifiers in something like "(?i:foo)" are represented by a
PPIx::Regexp::Token::GroupType::Modifier.
INHERITANCE
"PPIx::Regexp::Token::Modifier" is a PPIx::Regexp::Token.
"PPIx::Regexp::Token::Modifier" is the parent of
PPIx::Regexp::Token::GroupType::Modifier.
DESCRIPTION
This class represents modifier characters at the end of the regular
expression. For example, in "qr{foo}smx" this class would represent
the terminal "smx".
The "a", "d", "l", and "u" modifiers
The "a", "d", "l", and "u" modifiers, introduced into the "(?...)"
construction in Perl 5.13.6 (or 5.13.9 in the case of /a) are used to
force either Unicode pattern semantics ("u"), locale semantics ("l")
default semantics ("d" the traditional Perl semantics, which can also
mean 'dual' since it means Unicode if the string's UTF-8 bit is on, and
locale if the UTF-8 bit is off), or restricted default semantics ("a").
These are mutually exclusive, and only one can be asserted at a time.
Asserting any of these overrides the inherited value of any of the
others. The "asserted()" method reports as asserted the last one it
sees, or none of them if it has seen none.
For example, given "PPIx::Regexp::Token::Modifier" $elem representing
the invalid regular expression fragment "(?dul)", "$elem->asserted( 'l'
)" would return true, but "$elem->asserted( 'u' )" would return false.
Note that "$elem->negated( 'u' )" would also return false, since "u" is
not explicitly negated.
If $elem represented regular expression fragment "(?i)",
"$elem->asserted( 'd' )" would return false, since even though "d"
represents the default behavior it is not explicitly asserted.
Note that if this functionality is retracted before Perl 5.14 is
released, support for it will disappear. See "NOTICE" in PPIx::Regexp
for some explanation.
The caret ("^") modifier
Calling "^" a modifier is a bit of a misnomer. The "(?^...)"
construction was introduced in Perl 5.13.6, to prevent the inheritance
of modifiers. The documentation calls the caret a shorthand equivalent
for "d-imsx", and that it the way this class handles it.
For example, given "PPIx::Regexp::Token::Modifier" $elem representing
regular expression fragment "(?^i)", "$elem->asserted( 'd' )" would
return true, since in the absence of an explicit "l" or "u" this class
considers the "^" to explicitly assert "d".
Note that if this is retracted before Perl 5.14 is released, this
support will disappear. See "NOTICE" in PPIx::Regexp for some
explanation.
METHODS
This class provides the following public methods. Methods not
documented here are private, and unsupported in the sense that the
author reserves the right to change or remove them without notice.
asserts
$token->asserts( 'i' ) and print "token asserts i";
foreach ( $token->asserts() ) { print "token asserts $_\n" }
This method returns true if the token explicitly asserts the given
modifier. The example would return true for the modifier in "(?i:foo)",
but false for "(?-i:foo)".
If called without an argument, or with an undef argument, all modifiers
explicitly asserted by this token are returned.
match_semantics
my $sem = $token->match_semantics();
defined $sem or $sem = 'undefined';
print "This token has $sem match semantics\n";
This method returns the match semantics asserted by the token, as one
of the letters "a", "d", "l", or "u". If no explicit match semantics
are asserted, this method returns "undef".
modifiers
my %mods = $token->modifiers();
Returns all modifiers asserted or negated by this token, and the values
set (true for asserted, false for negated). If called in scalar
context, returns a reference to a hash containing the values.
negates
$token->negates( 'i' ) and print "token negates i\n";
foreach ( $token->negates() ) { print "token negates $_\n" }
This method returns true if the token explicitly negates the given
modifier. The example would return true for the modifier in
"(?-i:foo)", but false for "(?i:foo)".
If called without an argument, or with an undef argument, all modifiers
explicitly negated by this token are returned.
SUPPORT
Support is by the author. Please file bug reports at
<http://rt.cpan.org>, or in electronic mail to the author.
AUTHOR
Thomas R. Wyant, III wyant at cpan dot org
COPYRIGHT AND LICENSE
Copyright (C) 2009-2011 by Thomas R. Wyant, III
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl 5.10.0. For more details, see the full
text of the licenses in the directory LICENSES.
This program is distributed in the hope that it will be useful, but
without any warranty; without even the implied warranty of
merchantability or fitness for a particular purpose.
perl v5.14.1 2011-07-26 PPIx::Regexp::Token::Modifier(3)
