sub uhuu {
    my $keys = join "|", map "\Q$_\E", ($match_list =~ m{([^/,]+)/[^,]*}g);

    my %R;
    return unless $attrs =~ m{
        \A \Q$tag\E \s+
        (?: ($keys)=(\S+) (?(?{ defined $R{$1} || ($R{$1}=$2, 0) })(?!)) \s* )*+
        \z }x;

    $markup =~ s[X{($keys)}][ $R{$1} // $& ]ger
}