(run-hooks): Don't use mapcar--save consing.

(run-hook-with-args): New function.

1 files changed, 22 insertions, 1 deletions

diff --git a/lisp/subr.el b/lisp/subr.el
index 6da51773429..760d1edc22d 100644
--- a/lisp/subr.el
+++ b/lisp/subr.el
@@ -491,10 +491,31 @@ If it is a list, the elements are called, in order, with no arguments."
            (symbol-value sym)
            (let ((value (symbol-value sym)))
              (if (and (listp value) (not (eq (car value) 'lambda)))
-                 (mapcar 'funcall value)
+                 (let ((functions value))
+                   (while value
+                     (funcall (car value))
+                     (setq value (cdr value))))
                (funcall value)))))
     (setq hooklist (cdr hooklist))))
 
+(defun run-hook-with-args (hook &rest args)
+  "Run HOOK with the specified arguments ARGS.
+HOOK should be a symbol, a hook variable.  If HOOK has a non-nil
+value, that value may be a function or a list of functions to be
+called to run the hook.  If the value is a function, it is called with
+the given arguments and its return value is returned.  If it is a list
+of functions, those functions are called, in order,
+with the given arguments ARGS.
+It is best not to depend on the value return by `run-hook-with-args',
+as that may change."
+  (and (boundp hook)
+       (symbol-value hook)
+       (let ((value (symbol-value hook)))
+         (if (and (listp value) (not (eq (car value) 'lambda)))
+             (mapcar '(lambda (foo) (apply foo args))
+                     value)
+           (apply value args)))))
+
 ;; Tell C code how to call this function.
 (defconst run-hooks 'run-hooks
   "Variable by which C primitives find the function `run-hooks'.