Re: VIM can recognize #if 0 #endif as comment pair, how to do that in Emacs?

["Leo.Hou" <leo.hou@gmail.com>]

On Aug 17, 1:20 pm, da...@adboyd.com (J. David Boyd) wrote:
> "Leo.Hou" <leo....@gmail.com> writes:
> > Hi Experts,
>
> > I saw a friend using VIM and it recognizes #if 0 -- #endif as comment
> > pair and use the comment color for the code in between!
>
> > This is so cool because I had a big headache using emacs+etags jumping
> > into others' code, spent 5 minutes and then realized that emacs
> > brought me to some codes between a #if0 -- #endif pair. :'-(
>
> > Can anyone make Emacs to recognize this common convention and
> > highlight all the pieces between them as comment?
>
> > Thanks!
>
> > Leo
>
> Not _exactly_ what you are talking about, but I like this:
>
> >From C-h f hide-ifdef-mode
>
> hide-ifdef-mode is an interactive autoloaded Lisp function in `hideif'.
> (hide-ifdef-mode &optional arg)
>
> Toggle Hide-Ifdef mode.  This is a minor mode, albeit a large one.
> With arg, turn Hide-Ifdef mode on if arg is positive, off otherwise.
> In Hide-Ifdef mode, code within #ifdef constructs that the C preprocessor
> would eliminate may be hidden from view.  Several variables affect
> how the hiding is done:
>
> `hide-ifdef-env'
>         An association list of defined and undefined symbols for the
>         current buffer.  Initially, the global value of `hide-ifdef-env'
>         is used.
>
> `hide-ifdef-define-alist'
>         An association list of defined symbol lists.
>         Use `hide-ifdef-set-define-alist' to save the current `hide-ifdef-env'
>         and `hide-ifdef-use-define-alist' to set the current `hide-ifdef-env'
>         from one of the lists in `hide-ifdef-define-alist'.
>
> `hide-ifdef-lines'
>         Set to non-nil to not show #if, #ifdef, #ifndef, #else, and
>         #endif lines when hiding.
>
> `hide-ifdef-initially'
>         Indicates whether `hide-ifdefs' should be called when Hide-Ifdef mode
>         is activated.
>
> `hide-ifdef-read-only'
>         Set to non-nil if you want to make buffers read only while hiding.
>         After `show-ifdefs', read-only status is restored to previous value.
>
> Uses keymap "hide-ifdef-mode-map", which is not currently defined.- Hide quoted text -
>
> - Show quoted text -

Thanks David! I tried it and I loved it except for one thing: I need
to M-x hide-ifdefs every time I open a new file. Can i add some hooks
or something like that to keep it on forever?