Alternative variant of parse-verb-phrase
Louis Reasoner suggests that, since a verb phrase is either a verb or a verb phrase followed by a prepositional phrase, it would be much more straightforward to define the procedure
parse-verb-phrase
as follows (and similarly for noun phrases):
(define (parse-verb-phrase)
(amb (parse-word verbs)
(list 'verb-phrase
(parse-verb-phrase)
(parse-prepositional-phrase))))
Does this work? Does the program's behavior change if we interchange the order of expressions in the
amb
?