+(defvar *js-macros* nil)
+(defmacro define-js-macro (name lambda-list &body body)
+ (let ((form (gensym)))
+ `(push (cons ',name
+ (lambda (,form)
+ (block ,name
+ (destructuring-bind ,lambda-list ,form
+ ,@body))))
+ *js-macros*)))
+
+(defun js-macroexpand (js)
+ (if (and (consp js) (assoc (car js) *js-macros*))
+ (let ((expander (cdr (assoc (car js) *js-macros*))))
+ (multiple-value-bind (expansion stop-expand-p)
+ (funcall expander (cdr js))
+ (if stop-expand-p
+ expansion
+ (js-macroexpand expansion))))
+ js))
+
+