Re: debugging "Lisp nesting exceeds max-lisp-eval-dept" error??

[Stefan Monnier]

>     lazy-lock works OK.  The OP's problem has to do with some details of
>     how he turns it on.

> So, can we fix the mechanism for turning it on, so that customary ways
> of doing so will once again work ok?

Sure.  The infinite-lopping is the following:

  -> (font-lock-mode 1)
  -> (when (or noninteractive (eq (aref (buffer-name) 0) ?\ ))
       (setq font-lock-mode nil))
     ...
     (run-hooks 'font-lock-mode 'font-lock-mode-off)
  -> (turn-on-lazy-lock)
  -> (lazy-lock-mode 1)
  -> (if (not font-lock-mode) (font-lock-mode 1))
  -> (font-lock-mode 1)
  -> (when (or noninteractive (eq (aref (buffer-name) 0) ?\ ))
       (setq font-lock-mode nil))
     ...
     (run-hooks 'font-lock-mode 'font-lock-mode-off)
  -> (turn-on-lazy-lock)
  -> ...

So we can either change font-lock-mode so that calling (font-lock-mode 1)
always sets font-lock-mode to a non-nil value, as it should.
Or we can change lazy-lock-mode so it doesn't call font-lock-mode.

I think we should make both changes.

As mentioned, I'd also happily remove turn-on-lazy-lock.

All the above also applies to fast-lock.el.


        Stefan


--- orig/lisp/font-core.el
+++ mod/lisp/font-core.el
@@ -150,11 +150,12 @@
 your own function which is called when `font-lock-mode' is toggled via
 `font-lock-function'. "
   :group 'font-lock
-  ;; Don't turn on Font Lock mode if we don't have a display (we're running a
-  ;; batch job) or if the buffer is invisible (the name starts with a space).
-  (when (or noninteractive (eq (aref (buffer-name) 0) ?\ ))
-    (setq font-lock-mode nil))
-  (funcall font-lock-function font-lock-mode)
+  (funcall font-lock-function
+           ;; Don't turn on Font Lock mode if we don't have a display (we're
+           ;; running a batch job) or if the buffer is invisible (the name
+           ;; starts with a space).
+           (and (not (or noninteractive (eq (aref (buffer-name) 0) ?\ )))
+                font-lock-mode))
   ;; Arrange to unfontify this buffer if we change major mode later.
   (if font-lock-mode
       (add-hook 'change-major-mode-hook 'font-lock-change-mode nil t)


--- lazy-lock.el        22 aoû 2005 10:23:23 -0400      1.4
+++ lazy-lock.el        01 sep 2005 09:26:26 -0400      
@@ -522,8 +526,8 @@
                   (if arg (> (prefix-numeric-value arg) 0) (not was-on)))))
     (cond ((and now-on (not font-lock-mode))
           ;; Turned on `lazy-lock-mode' rather than `font-lock-mode'.
-          (let ((font-lock-support-mode 'lazy-lock-mode))
-            (font-lock-mode t)))
+           (message "Use font-lock-support-mode rather than calling 
lazy-lock-mode")
+           (sit-for 2))
          (now-on
           ;; Turn ourselves on.
           (set (make-local-variable 'lazy-lock-mode) t)