dcg.clj

gistfile1.clj

(def-->e verb [v]
  ([[:v 'eats]] '[eats]))

(def-->e noun [n]
  ([[:n 'bat]] '[bat])
  ([[:n 'cat]] '[cat]))

(def-->e det [d]
  ([[:d 'the]] '[the])
  ([[:d 'a]] '[a]))

(def-->e noun-phrase [n]
  ([[:np ?d ?n]] (det ?d) (noun ?n)))

(def-->e verb-phrase [n]
  ([[:vp ?v ?np]] (verb ?v) (noun-phrase ?np)))

(def-->e sentence [s]
  ([[:s ?np ?vp]] (noun-phrase ?np) (verb-phrase ?vp)))

(run* [parse-tree]
  (sentence parse-tree '[the bat eats a cat] []))

;; ([:s [:np [:d the] [:n bat]] [:vp [:v eats] [:np [:d a] [:n cat]]]])

;; ~70ms
(dotimes [_ 10]
  (time
    (dotimes [_ 1e3]
      (run* [parse-tree]
        (sentence parse-tree '[the bat eats a cat] [])))))