Re: c-mode and underscore

[Kevin Rodgers]

Xah Lee wrote:
> On Jul 7, 3:56 pm, geophile <jack.orenst...@gmail.com> wrote:
> > I am trying to get c-mode to treat underscore as a word, so that
> > forward-word backward-word don't stop on underscores.
> >
> > My .emacs file includes:
> >
> >     (modify-syntax-entry ?_ "w" c-mode-syntax-table)
> >
> > which does not appear to be effective. But if I run this command
> > manually, it is effective.
> >
> > I'm pretty sure that the line above is being reached in my .emacs
> > file, as later commands are effective.
>
> your code mod the global syntax table. you want to mode the syntax
> table for that mode. It works when u call manually because when u are
> in that mode, it mods that mod's syntax table.

How could c-mode-syntax-table refer to the current (not global) syntax
table?

> hook is a good solution.

It is consistent with the hypothesis that the problem is that
c-mode-syntax-table does not have its correct value when .emacs is
loaded.  Indeed, this code from progmodes/cc-mode.el reveals why it
is nil when .emacs is loaded and thus does refer to the current syntax
table as you said:

;;;###autoload
(defvar c-mode-syntax-table nil
  "Syntax table used in c-mode buffers.")
(or c-mode-syntax-table
    (setq c-mode-syntax-table
          (funcall (c-lang-const c-make-mode-syntax-table c))))

The autoload cookie causes the defvar to be copied into loaddefs.el
and thus dumped into the emacs executable.  Why does cc-mode.el do that
instead of the obvious

(defvar c-mode-syntax-table (funcall (c-lang-const 
c-make-mode-syntax-table c))
  "Syntax table used in c-mode buffers.")

> e.g.
>
> (add-hook 'w3m-mode-hook
>  (lambda ()
>   (define-key w3m-mode-map (kbd "<up>") 'previous-line) ; was w3m-
> previous-anchor. Use Shift+Tab.
>   (define-key w3m-mode-map (kbd "<down>") 'next-line) ; was w3m-next-
> anchor. Use Tab.
>   (define-key w3m-mode-map (kbd "<left>") 'backward-char) ; was w3m-
> view-previous-page. Use B.
>   (define-key w3m-mode-map (kbd "<right>") 'forward-char) ; was w3m-
> view-this-url. Use Enter.
> ))
>
> you want to find the syntax table name for that mode to modify.

If you're going to use a hook, you may as well just refer to the current
syntax table with (syntax-table) instead of by name.

--
Kevin Rodgers
Denver, Colorado, USA