;This function checks the arguments and
;determines if they specify a DCFL.
;If the arguments do not define a DCFL, 
;then it returns an appropriate error message.
;If the arguments do define a DCFL, then the function returns: 
;   An affirmation,
;   A list of the language's variables, and 
;   A list of the language's terminals.

;All output from this function - even the error 
;messages are returned as a list.
;There is not requirement for the output to be a list.
;However, returning it as a list allows for the use
;of the unit testing function.

(define DCFL-checker 
  (lambda 
    (
      axiom ; a list of atoms
      rules ; a list of lists of atoms.
      initialAngle ;real number [0, 360]
      turnAngle    ;real number [0, 180]
      shrinkage    ;real number [0.01, 100.0]
    ) 
    
    (define variableList '())
    (define terminalList '())
    (cond 
      ((not (atomlist? axiom)) 
          '("Error: axiom is not a list of atoms"))
      ((not (applyFunctionToList? atomlist? rules))
          '("Error: rules is not a list of a list of atoms"))
      ((not (checkRangeOfReal? initialAngle 0 360))
          '("Error: initialAngle must be between 0 and 360."))
      ((not (checkRangeOfReal? turnAngle 0 180))
          '("Error: turnAngle must be between 0 and 180."))
      ((not (checkRangeOfReal? shrinkage 0.01 100))
          '("Error: shrinkage must be between 0.01 and 100."))
      (else 
        (begin
          (set! variableList (getFirstAtomOfEach rules ))
          (cond 
            ((not (listOfUniqueAtoms? variableList))
              '("Error: Nondeterministic CFL")
            )
            (else
              ;At this point we are cool!
              ;No more errors to ckeck for.
              ;We already have the variableList complete.
              ;To build the terminalList we first cons
              ;the axiom list into the rules list.
              ;This new list will contain all of the 
              ;terminals and variables in the CFL.
              (set! terminalList 
                (extractUniqueAtoms 
                   (cons axiom rules))
              )
              ;Next, the variables need to be
              ;removed from the list.
              (set! terminalList 
                (removeListFromList variableList terminalList)
              )
              ;Build output list:
              (cons "Good DCFL"
               (cons "variables:"
                (cons variableList 
                  (cons "terminals:" 
                  (cons terminalList '())))))  
            )
          )
        )
      )
    )
  )
)


;============== Grading Rubric ==================
;The assignment is worth 20 points.
;Below are 17 test cases.
;Score one point for each test case that you pass.
;Score one point for having good comments.
;Score two points if John can quickly figure out 
;  how to download, save, run and test your code. 

;Unfortunately, for the grader, I did not specify the exact format 
;of the output. Therefore, John will not be able to use the 
;automatic testing program.



;============== Unit Tests ======================
(load "test.scm")
(load "atomlist.scm")
(load "checkRangeOfReal.scm")
(load "getFirstAtomOfEach.scm")
(load "listOfUniqueAtoms.scm")
(load "applyFunctionToList.scm")
(load "extractUniqueAtoms.scm")
(load "removeListFromList.scm")
(define msg "DCFL-checker")

(test msg 
   (DCFL-checker '(a b c) '((a a a) (b b b) (c c c)) 1 1 1) 
   '("Good DCFL" "variables:" (a b c) "terminals:" ())
)

(test msg 
   (DCFL-checker '(a a a) '((a b c d) (b b b) (c c c)) 1 1 1) 
   '("Good DCFL" "variables:" (a b c) "terminals:" (d))
)

(test msg 
   (DCFL-checker '(a a a) '((a b x y z) (b b b)) 1 1 1) 
   '("Good DCFL" "variables:" (a b) "terminals:" (x y z))
)

(test msg 
   (DCFL-checker '(a) '((a a x) (b y b) (c c c)) 1 1 1) 
   '("Good DCFL" "variables:" (a b c) "terminals:" (x y))
)

(test msg 
   (DCFL-checker '(a z) '((a a x) (b y b) (c c c)) 1 1 1) 
   '("Good DCFL" "variables:" (a b c) "terminals:" (z x y))
)

(test msg 
   (DCFL-checker '(a z) '((a a x) (c c c)) 1 1 1) 
   '("Good DCFL" "variables:" (a c) "terminals:" (z x))
)

(test msg 
   (DCFL-checker '(a b c) '((a a a)) 1 1 1) 
   '("Good DCFL" "variables:" (a) "terminals:" (b c))
)


(test msg 
   (DCFL-checker '(a b c) '((a a a) (b b b) (b c c)) 1 1 1) 
   '("Error: Nondeterministic CFL")
)

(test msg 
   (DCFL-checker '(a) '((a b c x) (b a x) (c a y) (b a a)) 1 1 1) 
   '("Error: Nondeterministic CFL")
)
 
(test msg 
   (DCFL-checker '(a b (c)) '((a a a)) 1 1 1) 
   '("Error: axiom is not a list of atoms")
)

(test msg 
   (DCFL-checker '(a b c) '((a a a) b (c c c)) 1 1 1) 
   '("Error: rules is not a list of a list of atoms")
)

(test msg 
   (DCFL-checker '(a b c) '((a a a) (b b b) (c (c c))) 1 1 1) 
   '("Error: rules is not a list of a list of atoms")
)

(test msg 
   (DCFL-checker '(a b c) '(() (b b b) (c c c)) 1 1 1) 
   '("Error: rules is not a list of a list of atoms")
)

(test msg 
   (DCFL-checker '(a) '((a a a)) -400 1 1) 
   '("Error: initialAngle must be between 0 and 360.")
)

(test msg 
   (DCFL-checker '(a) '((a b a)) 1 200 1) 
   '("Error: turnAngle must be between 0 and 180.")
)

(test msg 
   (DCFL-checker '(a) '((a b a)) 1 1 200) 
   '("Error: shrinkage must be between 0.01 and 100.")
)

(test msg 
   (DCFL-checker '(a) '((a b a)) 1 1 0) 
   '("Error: shrinkage must be between 0.01 and 100.")
)