Re: `special-form-p' again

[Stefan Monnier]

> There is no need to do this now, and maybe never.  Addition of new
> special forms is very very rare.

But then we should at least install the patch below, right?


        Stefan


--- advice.el   10 Oct 2006 17:06:28 -0400      1.47
+++ advice.el   02 Nov 2006 19:01:44 -0500      
@@ -2467,23 +2467,11 @@
   "Take a macro function DEFINITION and make a lambda out of it."
   `(cdr ,definition))
 
-;; There is no way to determine whether some subr is a special form or not,
-;; hence we need this list (which is probably out of date):
-(defvar ad-special-forms
-  (let ((tem '(and catch cond condition-case defconst defmacro
-                  defun defvar function if interactive let let*
-                  or prog1 prog2 progn quote save-current-buffer
-                  save-excursion save-restriction save-window-excursion
-                  setq setq-default unwind-protect while
-                  with-output-to-temp-buffer)))
-    ;; track-mouse could be void in some configurations.
-    (if (fboundp 'track-mouse)
-       (push 'track-mouse tem))
-    (mapcar 'symbol-function tem)))
-
-(defmacro ad-special-form-p (definition)
-  ;;"non-nil if DEFINITION is a special form."
-  (list 'memq definition 'ad-special-forms))
+(defun ad-special-form-p (definition)
+  "Non-nil iff DEFINITION is a special form."
+  (if (and (symbolp definition) (fboundp definition))
+      (setq definition (indirect-function definition)))
+  (and (subrp definition) (eq (cdr (subr-arity definition)) 'unevalled)))
 
 (defmacro ad-interactive-p (definition)
   ;;"non-nil if DEFINITION can be called interactively."