grammar pq;

token identifier
{
  hello

}

rule S
{
 <identifier>
}


sub parse ($str) {
    if ($str ~~ /<pq::S>/) {
        #return dumptree($/<XML::Grammar::Document::TOP>);
        #say $/.perl;
        #dump_node($/<easyregexp::TOP><root>);
                say $str;
    } else {
        return "no match";
    }
}

parse("hello");