PPIx::Regexp::Token::Modifier - Represent modifiers. |
a
, aa
, d
, l
, and u
modifiers^
) modifier
PPIx::Regexp::Token::Modifier - Represent modifiers.
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.
PPIx::Regexp::Token::Modifier
is a
PPIx::Regexp::Token.
PPIx::Regexp::Token::Modifier
is the parent of
PPIx::Regexp::Token::GroupType::Modifier.
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
.
a
, aa
, d
, l
, and u
modifiersThe a
, aa
, d
, l
, and u
modifiers, introduced starting in
Perl 5.13.6, 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.
^
) modifierCalling ^
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
.
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.
$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)
.
Starting with version 0.036_01, if the argument is a
single-character modifier followed by an asterisk (intended as a wild
card character), the return is the number of times that modifier
appears. In this case an exception will be thrown if you specify a
multi-character modifier (e.g. 'ee*'
), or if you specify one of the
match semantics modifiers (e.g. 'a*'
).
If called without an argument, or with an undef argument, all modifiers explicitly asserted by this token are returned.
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 strings 'a'
, 'aa'
, 'd'
, 'l'
, or 'u'
. If no explicit
match semantics are asserted, this method returns undef
.
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.
$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 is by the author. Please file bug reports at http://rt.cpan.org, or in electronic mail to the author.
Thomas R. Wyant, III wyant at cpan dot org
Copyright (C) 2009-2016 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.
PPIx::Regexp::Token::Modifier - Represent modifiers. |