parametric tokens/rules in Perl6 Grammars

param.p6

use v6.0.0;
use Test;

grammar Parametric {
    rule TOP { <header('foo')> <header('bar')> }
    
    token header($name, $sub-header = "{$name}-header") {
        ^^ [:i $name ] ':' <.ws> <::($sub-header)> \n
    }
    token foo-header { <[ab]>+ }
    token bar-header { <[cd]>+ }
}

sub test-it($str) {
    note $str.perl;
    my $result = Parametric.parse($str);
    ok $result, 'should match';
    note $/.perl;
}

subtest {
    test-it q:heredoc/END/;
    Foo: abababa
    Bar: cdcdcdcd
    END
},'simple case';

done-testing;