Modifying the Program for Strategies: Exercise 6.14, p. 159

• Exercise 6.14 adds a strategy parameter to the computer-move procedure.

• A strategy is simply a procedure that takes a game state and returns a move instruction. For example, here is the familiar simple-minded one currently used by the computer:

       (define simple-strategy
         (lambda (game-state)
           (if (> (size-of-pile game-state 1) 0) 
               (make-move-instruction 1 1)    ; remove one coin from pile 1
               (make-move-instruction 1 2)))) ; remove one coin from pile 2
  

• The computer will apply the strategy to the current game state and receive a move instruction, from which the number of coins and pile number can be extracted through the ADT selectors.

• Note that play-with-turns will need to be modified to accept a strategy parameter to be passed to computer-move, and nim will need to be modified to pass simple-strategy to play-with-turns.

• When you finish this exercise the program will still behave as it did before.