Re: Get rid of verilog-no-change-functions

[Stefan Monnier]

> 3. This code was originally developed on Emacs 21 so it's
> odd that inhibit-modification-hooks wasn't sufficient.

inhibit-modification-hooks was new in Emacs-21 and not widely known, so
I'm really not surprised.  Even nowadays it's still common to see people
let-binding after-change-functions instead of inhibit-modification-hooks.

> But the the verilog-mode.el code also works on ancient XEmacs.
> This is annoying for our code, but we still get bug reports
> occasionally so are reluctant to abandon it.  At a minimum
> inhibit-modification-hooks needs to be defined to prevent XEmacs
> compile warnings.

AFAIK my patch should work just as well at least for the
verilog-save-buffer-state part since XEmacs doesn't run
after-change-functions for text-property modifications.

For verilog-save-no-change-functions, I don't understand what is the
intention behind preventing after-change-functions (it intuitively seems
wrong, so I'm obviously missing something).

> +    (unless (boundp 'inhibit-modification-hooks)
> +      (defvar inhibit-modification-hooks nil))

No, no, no, no!
Just use

   (defvar inhibit-modification-hooks)

if you want to silence the byte-compiler.

But AFAIK as long you don't switch to "lexical-binding:t", no
byte-compiler will complain if you let-bind an unknown variable without
using it, so even that (defvar inhibit-modification-hooks) is
not indispensable.

> @@ -3231,6 +3233,7 @@ user-visible changes to the buffer must not be within a
>         (inhibit-read-only t)
>         (inhibit-point-motion-hooks t)
> +       (inhibit-modification-hooks t)  ; Emacs 21+
>         (verilog-no-change-functions t)
>         before-change-functions
>         after-change-functions
>         deactivate-mark

Here it's important to remove before-change-functions and
after-change-functions.

> @@ -3247,6 +3250,7 @@ user-visible changes to the buffer must not be within a
>  For insignificant changes, see instead `verilog-save-buffer-state'."
>    `(let* ((inhibit-point-motion-hooks t)
> +       (inhibit-modification-hooks t)
>         (verilog-no-change-functions t)
>         before-change-functions
>         after-change-functions)
>       (progn ,@body)))

As mentioned, here I'd have to understand why we need to prevent
*-change-functions from running.  After all, this is used in places
where we make very significant changes to the buffer and where font-lock
(for instance) would want to know about it.


        Stefan