gistfile1.txt

grammar G1 {
    token TOP { \d+ }
}
class G1Actions {
    method TOP($/) {
        make "G1: $/";
    }
}

grammar G2 {
    token TOP { \w+ }
}
class G2Actions {
    method TOP($/) {
        make "G2: $/";
    }
}

grammar G {
    token TOP {
        <g1=.LANG(G1, G1Actions)>
        <g2=.LANG(G2, G2Actions)>
    }
    
    method LANG($grammar, $actions) {
        $grammar.subparse(self.orig, :p(self.pos), :$actions).CURSOR
    }
}
class GActions {
    method TOP($/) {
        make "$<g1> and $<g2>";
    }
}
say G.parse("123beer", actions => GActions).ast;