New macro define-advice

* doc/lispref/functions.texi (Advising Named Functions): Document
define-advice.

* lisp/emacs-lisp/nadvice.el (define-advice): New macro.
* lisp/emacs-lisp/lisp-mode.el (lisp-imenu-generic-expression): Add
define-advice.
(lisp-font-lock-keywords-1): Add define-advice.

1 files changed, 24 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/nadvice.el b/lisp/emacs-lisp/nadvice.el
index bfd939d69e2..a81d3e43de3 100644
--- a/lisp/emacs-lisp/nadvice.el
+++ b/lisp/emacs-lisp/nadvice.el
@@ -441,6 +441,30 @@ of the piece of advice."
              (fset symbol (car (get symbol 'advice--saved-rewrite)))))))
   nil)
 
+;;;###autoload
+(defmacro define-advice (symbol args &rest body)
+  "Define an advice and add it to function named SYMBOL.
+See `advice-add' and `add-function' for explanation on the
+arguments.  Note if NAME is nil the advice is anonymous;
+otherwise it is named `SYMBOL@NAME'.
+
+\(fn SYMBOL (WHERE LAMBDA-LIST &optional NAME DEPTH) &rest BODY)"
+  (declare (indent 2) (doc-string 3) (debug (sexp sexp body)))
+  (or (listp args) (signal 'wrong-type-argument (list 'listp args)))
+  (or (<= 2 (length args) 4)
+      (signal 'wrong-number-of-arguments (list 2 4 (length args))))
+  (let* ((where         (nth 0 args))
+         (lambda-list   (nth 1 args))
+         (name          (nth 2 args))
+         (depth         (nth 3 args))
+         (props         (and depth `((depth . ,depth))))
+         (advice (cond ((null name) `(lambda ,lambda-list ,@body))
+                       ((or (stringp name) (symbolp name))
+                        (intern (format "%s@%s" symbol name)))
+                       (t (error "Unrecognized name spec `%S'" name)))))
+    `(prog1 ,@(and (symbolp advice) `((defun ,advice ,lambda-list ,@body)))
+       (advice-add ',symbol ,where #',advice ,@(and props `(',props))))))
+
 (defun advice-mapc (fun symbol)
   "Apply FUN to every advice function in SYMBOL.
 FUN is called with a two arguments: the function that was added, and the