I can't find the comment when exploring the result of this: RBParser parseExpression: 'aReceiver aMessage "foo" do: [Transcript show: 42]' onError: [:s :p|^nil].
But for this it's OK: RBParser parseExpression: 'aReceiver aMessage "foo" anotherMessage' onError: [:s :p|^nil].
(I'm porting a pretty printer from VW: package Gutenberg on SqueakSource)