8-Puzzle: Utilities for Manipulating States

(defun state-swap-pos (state pos1 pos2)

(let* ((tiles (state-tiles state))

(temp (nth pos1 tiles)))

(setf (nth pos1 tiles) (nth pos2 tiles))

(setf (nth pos2 tiles) temp)))

(defun state-add-action (state action)

(push action (state-actions state)))