;;; -*- Mode: Lisp; Package: USER -*-
;;;
;;; PPMX - pretty prints a macro expansion
;;;
;;; From the book "Common Lisp:  A Gentle Introduction to
;;;      Symbolic Computation" by David S. Touretzky.  
;;; The Benjamin/Cummings Publishing Co., 1990.
;;;
;;; Example of use:  (ppmx (incf a))


(defmacro ppmx (form)
  "Pretty prints the macro expansion of FORM."
  `(let* ((exp1 (macroexpand-1 ',form))
	  (exp (macroexpand exp1))
	  (*print-circle* nil))
     (cond ((equal exp exp1)
	    (format t "~&Macro expansion:")
	    (pprint exp))
	   (t (format t "~&First step of expansion:")
	      (pprint exp1)
	      (format t "~%~%Final expansion:")
	      (pprint exp)))
     (format t "~%~%")
     (values)))