; This is the test file for generating strings from context free grammars
;   for Assignment 3, CS 152, Fall 2003


(load "grammar.scm")


; You can uncomment this line out to enable tracing

; (require (lib "trace.ss"))


  ; This is a grammar for a fragment of English
  ; The rules are:
  ;   S -> NP VP
  ;  NP -> Det N  |  Det N PP
  ;  PP -> P NP
  ;  VP -> V      |  V NP     |  V PP   |  V N PP
  ;
  ; Note that the lexical categories P, V, N, and Det
  ;   are treated as terminal symbols

(define g (make-grammar 's
                        '(np vp pp)
                        (list (make-rule 's '(np vp))
                              (make-rule 'np '(det n))
                              (make-rule 'np '(np pp))
                              (make-rule 'pp '(p np))
                              (make-rule 'vp '(v))
                              (make-rule 'vp '(v np))
                              (make-rule 'vp '(v pp))
                              (make-rule 'vp '(v np pp)))))



  ; This is a simple grammar with rules
  ;    S -> x | x S S

(define g1 (make-grammar 's
                         '()
                         (list (make-rule 's '(x s s))
                               (make-rule 's '(x)))))



  ; This is a grammar for simple algebraic expressions.
  ; Its rules are
  ;   E -> T | T + E
  ;   T -> F | F * T
  ;   F -> x | y | < E >

(define g2 (make-grammar 'e
                        '(t f)
                        (list (make-rule 'e '(t))
                              (make-rule 'e '(t + e))
                              (make-rule 't '(f))
                              (make-rule 't '(f * t))
                              (make-rule 'f '(x))
                              (make-rule 'f '(y))
                              (make-rule 'f '(< e >))
                              )))

(define (test)
  (display (get-yields 's g 3))
  (newline)
  (display (get-yields 's g 4))
  (newline)
  (display (get-yields 's g 5))
  (newline)
  (display (get-yields 's g 6))
  (newline)
  (display (get-yields 's g 7))
  (newline)
  (display (get-yields 'vp g 6))
  (newline)
  (display (get-yields 's g 8))
  (newline)
  
  (display (get-yields 's g1 3))
  (newline)
  (display (get-yields 's g1 5))
  (newline)
  (display (get-yields 's g1 6))
  (newline)
  (display (get-yields 's g1 7))
  (newline)
  (display (get-yields 'vp g1 6))
  (newline)

  (display (get-yields 's g1 -6))
  (newline)
  (display (get-yields g g1 6))
  (newline)
  (display (get-yields 's 'e -6))
  (newline)

  (display (get-yields 'e g2 1))
  (newline)
  (display (get-yields 'e g2 3))
  (newline)
  (display (get-yields 'e g2 4))
  (newline)
  (display (get-yields 'e g2 5))
  (newline)
  (display (length (get-yields 'e g2 5)))
  (newline)
)