Re: A vision for multiple major modes [was: Re: [Emacs-diffs] widen-limits c331b66:]

[Alan Mackenzie <acm@muc.de>]

Hello, Vitalie.

On Wed, Mar 23, 2016 at 10:58:44PM +0100, Vitalie Spinu wrote:

> > To transcend the "unwanted widen" problem, there will be a very special
> > variable `restrict-to-island' or `restrict-to-span', 

> A second type of narrowing. That is what Stefan was insisting upon and that's
> what I will provide next patch for.

A type of narrowing is not a good way of thinking about it.

> > Although the above vision implies a lot of development work, there is
> > nothing there which is beyond our abilities to implement readily.  It
> > would give us a true multi major mode capability, yet the impact on
> > individual major modes would be minimal.

> A lot of development work is already happening in various generic multi-mode
> engines. It's hard, but feasible and stuff mostly works without changing any of
> the existing code.

It "mostly" works, sort of, from what I can gather in threads like this
one.  My impression is that with better support in the Emacs core, it
could work fully, without unlovely artifices.

But nobody else has so far shown much interest, so it seems it won't
happen.

> Making parse-partial-sexp understand islands won't give much.

That was not what my post, to which you are replying, was about.  It was
far more ambitious than that.

> You can already do that well enough by advising syntax-ppss.

I doubt that very much.  syntax-ppss is just one of many ways of using
parse-partial-sexp.  But I'd love to see the code.  Has it been
committed, and if so, into which branch?

>   Vitalie

-- 
Alan Mackenzie (Nuremberg, Germany).