Re: [Emacs-diffs] scratch/widen-less a4ba846: Replace prog-widen with consolidating widen calls

[Dmitry Gutov <dgutov@yandex.ru>]

On 12/2/17 8:28 PM, Alan Mackenzie wrote:

> It would work, and work well, for the simple reason it is a coherent
> proposal.

I've never seen a full proposal. Details matter. And it's going to have 
to include a lot more of them.

> Emacs was designed with the assumption that each buffer has exactly one
> major mode.  It turns out this assumption hasn't held all that well.
> When that assumption does hold, the following returns a well defined and
> meaningful state:
> 
>      (parse-partial-sexp 1 n)
> 
> .  I am proposing extending this property for buffers with several
> modes and several syntax tables.  Nothing more, nothing less.

Extending parse-partial-sexp to nested syntax tables can be worthwhile, 
but that can't be it. And while we're on this subject, there are some 
example of Ruby syntax that we'd like to see supported, where the 
current syntax tables (and even syntax-propertize-function) don't cut it.

I'm not convinced "several syntax tables" would be enough, though.

> You're saying that providing support for multiple major modes in the
> Emacs core is a pipe dream.  I put it to you you're mistaken.  ONLY by
> supporting this in the Emacs core can we arrive at a coherent efficient
> design.

The major modes will have to change to allow for this support, that's 
for sure. You can't expect no code changes.

> The fact we are having this conversation is a strong indication
> that the current designs for MMM are not coherent enough.

The current idea is "let's do the minimum coherent step forward, so that 
somebody can continue improving things later". A step that's easy to 
use, and also easy to undo later, if we find something else that's much 
better.

Coming up with it was not easy at all, BTW.

>> Also, I don't think major modes need more freedom in how to implement
>> things.  Instead, they need more help so they can just use existing
>> solutions rather than reinvent the wheel in their very own way.
>> Conventions/guidelines actually makes the life of major mode
>> implementers easier, rather than harder.
> 
> That is immensely patronising.

It's simply description of good engineering. You can try to criticize 
the details of syntax-propertize, but the idea of reusing common 
solutions is more than sound.