feature/native-comp d07d7ab 1/2: Add `advice-flet' macro

[Andrea Corallo]

branch: feature/native-comp
commit d07d7ab1a0e321ced62ebe5dd9db27eb7e93430e
Author: Andrea Corallo <akrl@sdf.org>
Commit: Andrea Corallo <akrl@sdf.org>

    Add `advice-flet' macro
    
    The testsuite does large use of primitive redefinition, to avoid that
    we define `advice-flet' to use instead as an easy `cl-letf'
    replacement.
    
        * lisp/emacs-lisp/nadvice.el (advice-flet): New macro.
---
 lisp/emacs-lisp/nadvice.el | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/lisp/emacs-lisp/nadvice.el b/lisp/emacs-lisp/nadvice.el
index 5b3aa70..21da038 100644
--- a/lisp/emacs-lisp/nadvice.el
+++ b/lisp/emacs-lisp/nadvice.el
@@ -356,6 +356,32 @@ of the piece of advice."
     (macroexp-let2 nil new `(advice--remove-function ,getter ,function)
       `(unless (eq ,new ,getter) ,(funcall setter new)))))
 
+;;;###autoload
+(defmacro advice-flet (bindings &rest body)
+  ;; FIXME add doc.
+  (declare (indent 1))
+  (let ((let-binds ())
+        (ad-add ())
+        (ad-del ()))
+    (dolist (bind bindings)
+      (let* ((fun-name (car bind))
+             (fun (cadr bind))
+             (tmp-sym (gensym (symbol-name fun-name))))
+        (push `(,tmp-sym ,fun) let-binds)
+        (push `(advice-add #',fun-name
+                           ,(if (= (length bind) 3)
+                                (nth 2 bind)
+                              :override)
+                           ,tmp-sym)
+              ad-add)
+        (push `(advice-remove #',fun-name ,tmp-sym) ad-del)))
+    `(let ,(reverse let-binds)
+       (unwind-protect
+          (progn
+            ,@(reverse ad-add)
+            ,@body)
+        ,@(reverse ad-del)))))
+
 (defun advice-function-mapc (f function-def)
   "Apply F to every advice function in FUNCTION-DEF.
 F is called with two arguments: the function that was added, and the