para

use CSS::Minifier::Document;
use CSS::Minifier::Plugin;
use CSS::Minifier::Util;

class CSS::Minifier::Plugin::Merging:ver<0.0.14>:auth<zef:sasha> does CSS::Minifier::Plugin {
    method name(--> Str) { 'merging' }

    method run(Document $doc --> Nil) {
        $doc.statements = self!merge-same-declarations($doc.statements);
        $doc.statements = self!merge-adjacent-same-selectors($doc.statements);
        self!dedup-selector-lists($doc.statements);
    }

    # --- Same-declaration merging ---
    # Adjacent rulesets with identical declarations have their
    # selectors combined into a comma-separated list.
    method !merge-same-declarations(Statement @stmts) {
        my Statement @result = self!merge-same-in-list(@stmts);
        for @result -> $stmt {
            if $stmt ~~ AtRule {
                $stmt.statements = self!merge-same-declarations($stmt.statements);
            }
        }
        @result;
    }

    method !merge-same-in-list(Statement @stmts --> Array[Statement]) {
        my Statement @merged;
        my int $i;

        while $i < @stmts {
            my $current = @stmts[$i];
            $i++;

            given $current {
                when RuleSet {
                    unless .declarations {
                        @merged.push: $current;
                        next;
                    }
                    # Same-decl-key merge would drop custom property duplicates
                    if .declarations.first({ is-custom-prop(.property) }) {
                        @merged.push: $current;
                        next;
                    }

                    my $cur = $_;
                    $cur.decl-key ||= declarations-to-key($cur.declarations);

                    while $i < @stmts {
                        my $next = @stmts[$i];
                        given $next {
                            when RuleSet {
                                unless .declarations { $i++; next }
                                $next.decl-key = declarations-to-key($next.declarations) unless $next.decl-key;
                                last unless $next.decl-key eq $cur.decl-key;
                                $current.selectors.append: .selectors;
                            }
                            when AtRule {
                                if .declarations || .statements || .trailing-declarations || .braceless { last }
                                $i++;
                                next;
                            }
                        }
                        $i++;
                    }
                    @merged.push: $current;
                }
                when AtRule {
                    @merged.push: $current;
                }
            }
        }

        @merged;
    }

    # --- Same-selector merging ---
    # Adjacent rulesets with the same selectors have their
    # declarations combined (respecting !important).
    method !merge-adjacent-same-selectors(Statement @stmts) {
        my Statement @result = self!merge-sel-in-list(@stmts);
        for @result -> $stmt {
            if $stmt ~~ AtRule {
                $stmt.statements = self!merge-adjacent-same-selectors($stmt.statements);
            }
        }
        @result;
    }

    method !merge-sel-in-list(Statement @stmts --> Array[Statement]) {
        my Statement @merged;
        my int $i;

        while $i < @stmts {
            my $current = @stmts[$i];
            $i++;

            given $current {
                when RuleSet {
                    unless .declarations {
                        @merged.push: $current;
                        next;
                    }

                    my @cur-sel = $current.selectors.sort.Array;
                    my %by-prop;
                    %by-prop{is-custom-prop(.property) ?? .property !! .property.lc} = $_ for $current.declarations;
                    while $i < @stmts {
                        my $next = @stmts[$i];
                        given $next {
                            when RuleSet {
                                unless .declarations { $i++; next }
                                my @next-sel = $next.selectors.sort.Array;
                                last unless @cur-sel eqv @next-sel;
                                self!merge-decls($current, $next, %by-prop);
                            }
                            when AtRule {
                                last if .declarations || .statements || .trailing-declarations || .braceless;
                                $i++;
                                next;
                            }
                        }
                        $i++;
                    }
                    @merged.push: $current;
                }
                when AtRule {
                    @merged.push: $current;
                }
            }
        }

        @merged;
    }

    method !merge-decls(RuleSet $target, RuleSet $source, %by-prop --> Nil) {
        for $source.declarations -> $sd {
            my $key = is-custom-prop($sd.property) ?? $sd.property !! $sd.property.lc;
            if %by-prop{$key} -> $td {
                unless $td.important && !$sd.important {
                    $td.value     = $sd.value;
                    $td.important = $sd.important;
                    $td.normalized = Nil;
                }
            } else {
                my $new = Declaration.new(:property($sd.property), :value($sd.value), :important($sd.important));
                $target.declarations.push: $new;
                %by-prop{$key} = $new;
            }
        }
        $target.decl-key = Str;
    }

    # --- Selector list dedup ---
    method !dedup-selector-lists(Statement @stmts --> Nil) {
        for @stmts -> $stmt {
            given $stmt {
                when RuleSet {
                    my @uniq;
                    my %seen;
                    for .selectors -> $sel {
                        %seen{$sel}++ or @uniq.push: $sel;
                    }
                    .selectors = @uniq if @uniq.elems != .selectors.elems;
                }
                when AtRule {
                    self!dedup-selector-lists(.statements);
                }
            }
        }
    }
}



head

CSS::Minifier::Plugin::Merging — ruleset merging for the CSS minifier


Performs two types of structural merging at level 2:


item

This library is free software; you can redistribute it and/or modify
it under CC0.


root

Plugin

Dedup

React

=begin React :component<HeaderCol> :id<menu> 
=para L<Documentation|/doc/introduction>
=para L<Modules| /mods>
=para L<Examples| file:../examples/index.podlite>
=para L<AI|file:../mcp/index.podlite>
=para L<Download |file:../download/index.podlite>
=para L<About|file:../about/index.podlite>
=para 🔍 K<⌘K>/K<ctrl-K>
=end React


=begin React :component<HeaderCol> :id<footer>  
=begin nested :!nested
=item1 B<Language>
    =item2 L<Get started|file:../getting-started/getting-started.podlite>
    =item2 L<Why Raku?|/doc/language/faq#Why-should-I-learn-Raku-What's-so-great-about-it>
    =item2 L<Try Raku|https://glot.io/new/raku>
    =item2 L<Download | file:../download/index.podlite>
    =item2 L<Raku cheat sheet|https://github.com/Raku/mu/blob/master/docs/Perl6/Cheatsheet/cheatsheet.txt>
    =item2 L<Raku on Exercism|https://exercism.org/tracks/raku>
    =item2 L<Wikipedia|https://en.wikipedia.org/wiki/Raku_(programming_language)>

=end nested
=begin nested :!nested

=item1 B<L<Documentation|/doc>>
    =item2 L<Getting started, Migration guides from other languages, & Tutorials | file:../doc/introduction.podlite>
    =item2 L<Language References|file:../doc/reference.podlite>
    =item2 L<Type Reference| file:../doc/types.podlite>
    =item2 L<Miscellaneous| file:../doc/miscellaneous.podlite>
    =item2 L<FAQs (Frequently Asked Questions)|/doc/language/faq>
    =item2 L<Community|/doc/language/community>
    =item2 L<The list of all documents|file:../doc/index.podlite>
    =item2 L<Hand these documents to an AI assistant|file:../mcp/index.podlite>

=end nested
=begin nested :!nested
=item1 B<Learning>
    =item2 L<The Raku Guide|https://raku.guide/>
    =item2 L<Wikibook |https://en.wikibooks.org/wiki/Raku_Programming>
    =item2 L<Books |https://perl6book.com/>
    =item2 L<Rosetta Code | https://www.raku.org/community/rosettacode>
    =item2 L<Learn Raku in Y minutes|https://learnxinyminutes.com/docs/raku/>
    =item2 L<Golfing |https://github.com/AlexDaniel/raku-golf-cheatsheet>
=end nested
=begin nested :!nested

=item1 B<Explore>
    =item2 L<Raku Blog Aggregator|https://planet.raku.org/>
    =item2 L<Rakudo Weekly|https://rakudoweekly.blog/>
    =item2 L<The Weekly Challenge |https://perlweeklychallenge.org/>
    =item2 L<Raku Advent Calendar|https://raku-advent.blog/>

=end nested
=end React


Built with L<Podlite|https://podlite.org> — the markup and publishing tools behind this site.


=begin React :component<CookieConsent> :id<CookieConsent> :buttonCaption("Got it!")
=para
This website uses cookies for analytics.
=end React


Merging

NAME

DESCRIPTION

AUTHOR

COPYRIGHT AND LICENSE

CSS::Minifier v0.0.14

Authors

License

Dependencies

Test Dependencies

Provides

Documentation