(in-package :polyominos)

(defmacro aif (test then &optional else)
  `(let ((it ,test))
     (if it ,then ,else)))

(defmacro nor (&rest args)
  `(not (or ,@args)))

(defmacro awhen (test &rest then)
  `(let ((it ,test))
     (when it
       (progn
         ,@then))))

(defmacro acond (&rest clauses)
  (if (null clauses)
      nil
    (let ((cl1 (car clauses))
          (sym (gensym)))
      `(let ((,sym ,(car cl1)))
         (if ,sym
             (let ((it ,sym)) ,@(cdr cl1))
           (acond ,@(cdr clauses)))))))

(defmacro while (test &rest body)
  "So, old habits are hard to break..."
  `(do ()
       ((not ,test))
     ,@body))

;; Pieces are rotates before they are made into vectors
(defun rotate (piece-rep)
  "Rotate a block 90 degrees counter-clockwise."
  (flet ((rotate-section (section)
			    (if (null section) 
				nil 
			      (append (cdr section) 
				      (list (car section))))))
    (let ((width (length (car piece-rep)))
	  (result '()))
      (dotimes (i width)
	(setq result (cons 
		      (mapcar #'rotate-section
			      (mapcar #'(lambda (l) 
					  (elt l i)) piece-rep)) 
		      result)))
      result)))

;; $Id: //info.ravenbrook.com/user/ndl/lisp/contest/entries/anthony-juckel/solution1/utils.lisp#1 $