evil

my $i3_packet_grammar = qr{
    # Start
    <nocontext:>
    <map> | <array>

    <rule: map>
        \(\[ <[entry]>+ % ( , ) \]\)
        (?{ my $tmp = {};
            my $arr = $MATCH{entry};
            foreach my $i (@$arr) {
                my @keys = keys(%$i);
                foreach my $k (@keys) {
                    $tmp->{$k} = $i->{$k};
                };
            };
            $MATCH = $tmp;
            })

    <rule: entry>
        <key=string> \: <value>
        (?{ $MATCH = { $MATCH{key} => $MATCH{value} } })

    <rule: array>
        \(\{ <[value]>+ % ( , ) \}\)
        (?{ $MATCH = $MATCH{value} })

    <rule: value>
        <string>
        (?{ $MATCH = $MATCH{string} })
        | <number>
        (?{ $MATCH = $MATCH{number} })
        | <map>
        (?{ $MATCH = $MATCH{map} })
        | <array>
        (?{ $MATCH = $MATCH{array} })

    <token: string>
        ( \".*?(?<!\\)\" )
        <MATCH= (?{ unescape_string( $CAPTURE ); })>

    <token: number>
        ( [+-]?[0-9]*\.?[0-9]+(?:[eE][+-]?[0-9]+)? )
        <MATCH= (?{ $CAPTURE + 0; })>

}xms;