01_grammar_custom_method.p6

#!/usr/bin/env perl6
 
grammar Foo {
    token TOP { <custom(42)> "a" }
    
    method custom ($cursor: $n) {
#         say $cursor.^mro;
#         say $cursor.^methods>>.name;
        
        return $cursor;
    }
}

say Foo.parse("a");

02_grammar_custom_method.out

P6opaque: no such attribute '$!pos'
  in regex TOP at ./01_grammar_custom_method.p6:4
  in block <unit> at ./01_grammar_custom_method.p6:14