; CSCI 4150 Intro. to AI, Fall 2005
; Assignment 4, create-c4-player (Problem 2) and c4-eval (Problems 3 and 6)
; 
(load "a4code")    ; don't change these lines!
(load "connect4")

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;
; Problem 2
;
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; Here's a possible "create-c4-player" procedure.  Note that this is a
; procedure that returns a procedure created by a lambda form.
;
; Remember that your "create-c4-player" must be able to run with any
; evaluation function --- it cannot be specialized for only your
; evaluation function.
;
; This procedure is only a suggestion.  It assumes that the ab-minimax
; function takes the four arguments as I've given them here and that
; it returns the best move.  You may want to do this differently when
; you implement the alpha-beta minimax search, but if not, you can
; just use the procedure below.
;
(define (create-c4-player eval-fn depth-cutoff)
  ; the "player procedure" returned must take the following arguments:
  (lambda (board player-symbol)
    (let ((m (get-opening-db-move board)))
      (if m ; if there was a move specified in the opening database
          ; then return it
	  m 
	  ; otherwise, call alpha-beta minimax
	  (ab-minimax board
		      player-symbol
		      eval-fn
		      depth-cutoff)))))

; IMPORTANT!!!
;
; In your alpha-beta minimax, you must evaluate the children in the
; order that they are given to you by c4-children.  Otherwise your code
; will not test properly on the web tester.
;