title: Is there a way to run an action on a grammar that's already been parsed?
body: <p>If I do:</p>
  <pre><code>my $parsed_grammar = PG.parse( $some_string );
  </code></pre>
  <p>Is there any way to to do something like the pseudo code below?</p>
  <pre><code>$parsed_grammar.run_action( $action_class.new );
  </code></pre>