(in-package :ometa)
(declaim (optimize (safety 3) (debug 3)))

(defun ometa-optimize (form)
  (case (first form)
    ((:and  and) (let ((clauses (cdr form)))
		  (if (null clauses)
		      nil
		      (if (= (length clauses) 1)
			  (ometa-optimize (first clauses)) 
			  (let ((remaining (loop for f in clauses when (ometa-optimize f) collect it)))
			    (if (> (length remaining) 1)
				`(:and ,@remaining)
				(ometa-optimize `(and ,@remaining))))))))
    ((:or  or) (let ((clauses (cdr form)))
		(if (null clauses)
		    nil
		    (if (= (length clauses) 1)
			(ometa-optimize (first clauses)) 
			`(:or ,@(loop for f in clauses when (ometa-optimize f) collect it))))))
    ((prod :rule) `(:rule ,(second form) ,(third form) ,(ometa-optimize (fourth form))))
    ((:assign  assign) `(:assign ,(second form) ,(ometa-optimize (third form))))
    (otherwise form)))