Test lexicon and grammar for the LISP recursive-descent parser

; cf_grammar2.lm

(define (member? sym set)
	(pair? (member sym set)))

(define (nonterminal? sym)
  (member?
    sym
    '(s np vp pp)))

(define (terminal? sym)
  (member?
    sym
    '(det n v p)))

(define (lexicon category word)
  (member?
    word
    (assoc
      category
      '((det the this)
        (n man woman park jack jill)
        (v visited saw)
        (p near in with)))))

(define (productions sym)
  (cdr
    (assoc
      sym
      '(
        (s
          (np vp)
          (np vp pp)
        )
        (np
          (n)
          (det n)
          (n pp)
          (det n pp)
        )
        (pp
          (p np)
        )
        (vp
          (v)
          (v np)
          (v pp)
          (v np pp)
        )))))

(define (start-symbol)
  's)