Re: [Emacs-diffs] master 51e7e46: Font-lock elisp macros/special forms dynamically

[Tassilo Horn]

Stefan Monnier <address@hidden> writes:

>> Finally, I'm positively surprised at how fast the update function is.
>> I would have expected some lag, but haven't found any (even though I'm
>> looking).
>
> Loading Elisp files should be fairly rare.  But there might be cases
> where it can be done repeatedly, but if/when faced with such a situation
> we should be able to handle it efficiently e.g. by checking the
> load-history (make sure the file did include some definitions before we
> bother to scan symbols and rebuild the regexp) since such "run-time
> loading" probably won't define new functions.

Like so?

--8<---------------cut here---------------start------------->8---
diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index b4f87fd..f8591aa 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -198,9 +198,21 @@ Return non-nil only if the old and new value are 
different."
          (concat "(" (regexp-opt elisp-macros t) "\\_>"))
     (not (string= old-regex lisp--el-macro-regexp))))
 
-(defun lisp--el-update-after-load (_file)
+(defun lisp--el-update-after-load (file)
   "Update `lisp--el-macro-regexp' and adjust font-lock in existing buffers."
-  (when (lisp--el-update-macro-regexp)
+  (when (and
+        ;; Don't trigger when a file gets reloaded.
+        (string= file (caar load-history))
+        ;; Test if the recently loaded file defined any new macros.
+        (let ((load-entries (cdar load-history)))
+          (catch 'found
+            (while load-entries
+              (when (and (consp (car load-entries))
+                         (eq 'defun (caar load-entries))
+                         (macrop (cdar load-entries)))
+                (throw 'found t))
+              (setq load-entries (cdr load-entries)))))
+        (lisp--el-update-macro-regexp))
     (dolist (buf (buffer-list))
       (when (derived-mode-p 'emacs-lisp-mode)
        (font-lock-flush)))))
--8<---------------cut here---------------end--------------->8---

Bye,
Tassilo