quadricode.lisp

(defmacro count-macro-expansions (&body body)
  "Count the number of macro expansions required to execute
BODY. Return two values: the result of executing BODY and the
number of expansions."
  (let ((closures (gensym "CLOSURES-")))
    `(let* ((,closures
             (funcall
              (compile nil
                       `(lambda ()
                          (let ((count 0))
                            (cons (lambda (expander form env)
                                    (incf count)
                                    (funcall expander form env))
                                  (lambda () count)))))))
            (*macroexpand-hook* (car ,closures)))
       (values (progn ,@body)
               (funcall (cdr ,closures))))))