PPIx::R...Modifier(3)

💖 PPIx::Regexp::Token::Modifier 💖

okay bestie, welcome to the PPIx::Regexp::Token::Modifier page, from the User Contributed Perl Documentation crew, section 3 of the manual. she's the one who handles modifiers. periodt. ✨

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🌸 NAME 🌸

PPIx::Regexp::Token::Modifier — Represent modifiers. that's it, that's the whole job, and she ate 💅

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🦋 SYNOPSIS 🦋

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

so like, the trailing smx in that regex? that's her. that's this class. she represents it 💖

and not just the tail end either — she also represents the whole of things like (?ismx). but heads up, the modifiers inside something like (?i:foo) are a whole different girl, they're represented by a PPIx::Regexp::Token::GroupType::Modifier. iykyk 🌈

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👑 INHERITANCE 👑

PPIx::Regexp::Token::Modifier is a PPIx::Regexp::Token.

and PPIx::Regexp::Token::Modifier is the parent of PPIx::Regexp::Token::GroupType::Modifier. family tree slay 🌳✨

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✨ DESCRIPTION ✨

This class represents modifier characters at the end of the regular expression. Like, for example, in qr{foo}smx this class would represent the terminal smx. iconic behaviour honestly 🎀

💜 The a, aa, d, l, and u modifiers

The a, aa, d, l, and u modifiers got introduced starting in Perl 5.13.6, and they're here to force a specific flavour of pattern semantics:

• u — Unicode pattern semantics
• l — locale semantics
• d — default semantics (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)
• a — restricted default semantics

These are mutually exclusive bestie. only one can be asserted at a time. asserting any of these overrides the inherited value of any of the others. and the asserted() method reports as asserted the last one it sees — or none of them at all if it has seen none. no cap 👑

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. and side note — $elem->negated( 'u' ) would also return false, since u is not explicitly negated. she's just... not there. not negated, just absent 💀

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. like, she's the default but she didn't say it, so she doesn't get credit 🫶

🎀 The caret (^) modifier

okay so calling ^ a modifier is a bit of a misnomer, lowkey. 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 is the way this class handles it.

For example, given PPIx::Regexp::Token::Modifier $elem representing regular expression fragment (?^i), $elem->asserts( 'd' ) would return true, since in the absence of an explicit l or u this class considers the ^ to explicitly assert d. 🔥

The caret handling is complicated by the fact that the n modifier was introduced in 5.21.8, at which point the caret became equivalent to d-imnsx. The author did not feel he could unconditionally add the -n to the expansion of the caret, because that would produce confusing output from methods like explain(). Nor could he make it conditional on the minimum perl version, because that information is not available early enough in the parse. What he did was to expand the caret into d-imnsx if and only if n was in effect at some point in the scope in which the modifier was parsed. okay that's actually so clever of him 🧚

Continuing the above example, $elem->asserts( 'n' ) and $elem->modifier_asserted( 'n' ) would both return false, but $elem->negates( 'n' ) would return true if and only if the /m modifier has been asserted somewhere before and in-scope from this token. The modifier_asserted( 'n' ) method is inherited from PPIx::Regexp::Element. 💅

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🌟 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. so like, don't get attached to the undocumented ones 🙈

⭐ 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). like, the second one is doing the opposite bestie 😭

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*'). ⚠️

If called without an argument, or with an undef argument, all modifiers explicitly asserted by this token are returned. all of them. the whole squad 🫶

⭐ 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 strings 'a', 'aa', 'd', 'l', or 'u'. If no explicit match semantics are asserted, this method returns undef. vibe check: undefined 😌

⭐ 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. two contexts, two moods, both valid 💜

⭐ 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). the minus sign is doing so much work here 🔥

If called without an argument, or with an undef argument, all modifiers explicitly negated by this token are returned. ✨

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🫶 SUPPORT 🫶

Support is by the author. Please file bug reports at <https://github.com/trwyant/perl-PPIx-Regexp/issues> or in electronic mail to the author. he genuinely wants to hear from you bestie 💌

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🌈 AUTHOR 🌈

Thomas R. Wyant, III — harryfmudd at comcast dot net 👑

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💖 COPYRIGHT AND LICENSE 💖

Copyright (C) 2009-2023, 2025-2026 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. (that's legalese for "no promises, bestie, but she's trying her best" 😭)

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and that's the whole page!! go forth and parse some modifiers, you absolute icon 🦋

kisses, this was PPIx::Regexp::Token::Modifier from perl v5.42.2, dated 2026-06-15, out of the User Contributed Perl Documentation collection. mwah 💅💖🌸