[Orgmode] Re: [PATCH] Indent code with TAB in Org buffer

[Carsten Dominik]

Hi Dan,

On Aug 16, 2010, at 1:00 AM, Dan Davison wrote:

> Carsten Dominik <address@hidden> writes:
>
> > On Aug 15, 2010, at 8:43 AM, Dan Davison wrote:
> >
> > > With this patch TAB in a code block aligns the code according to the
> > > major mode. The macro could be used to do the same thing for other
> > > commands (i.e. allow other commands to be invoked in the Org buffer,
> > > but
> > > actually carried out in the code buffer.)
> > >
> > > Patch attached and in branch src-block-tab at
> > > address@hidden:dandavison/org-devel.git.
> > >
> > > diff --git a/lisp/org-src.el b/lisp/org-src.el
> > > index baa2b11..fc15a83 100644
> > > --- a/lisp/org-src.el
> > > +++ b/lisp/org-src.el
> > > @@ -435,6 +435,19 @@ the fragment in the Org-mode buffer."
> > >      (message "%s" msg)
> > >      t)))
> > >
> > > +(defmacro org-src-do-in-edit-buffer (&rest body)
> > > +  "Evaluate BODY in edit buffer if there is a code block at point.
> > > +Return t if a code block was found at point, nil otherwise."
> > > +  `(when (org-edit-src-code)
> >
> > Wow, an excursion to the temp buffer for every TAB call
> > in a source code block?
> >
> > Sounds heavy.  But I see that it could be nice together with
> > the new fontification stuff.  My gut feeling would be to have
> > both of these feature off by default.  But I have not tried
> > them yet.
>
> Hi Carsten,
>
> In a small code block the TAB is actually not bad at all, but in a big
> one there's a delay (that's worst case scenario: a netbook with an  
> atom
> processor).
>
> I think it's clear that automatic fontification as you type by emacs
> font-lock should be turned off by default. We could consider
> fontification of code blocks e.g. on start up, and when
> folding/unfolding, but let's discuss that in a separate thread.

Yes, this does make sense.  Although I am worried about thing which
increase the org-mode startup time significantly, because Org often
pulls in a lot of files to scan them, and time spent when initializing
the mode would hurt all these processes.  I guess we can figure out
all of this - maybe with a minor mode called org-live-code-mode or
something which can turn on various features in this direction.

It might also be possible to implement this in a much more efficient
way.  For example, we could keep a indirect buffer for the
source snippet which was modifed most recently.  That buffer could
be narrowed to the snippet, and executing TAB and fontification
could be done in that indirect buffer which would have the correct mode,
etc.  Whenever we edit the code, we could have an overlay with  
modification hooks
which would just copy the fontification overlays from the indirect  
buffer.
That should be a lot faster that creating a buffer, initializing a  
mode etc.

- Carsten