Re: Bug #25608 and the comment-cache branch

[Dmitry Gutov]

On 12.02.2017 14:05, Alan Mackenzie wrote:

> That's incoherent.  comment-cache was never intended to help those other
> uses, though it appears it could do so for most of them.  That
> particular flaw we're talking about doesn't appear in comment cache, so
> there's nothing to fix there.

You're changing a low-level primitive to adhere to a non-flexible view 
of the world that is incompatible with syntax-ppss.

> Maybe sometime.  In the meantime, the bug with open parens in column
> zero in comments should be fixed.

If you're willing to give up narrowing support, that bug can be fixed in 
no time, with the 20-line patch we all know about.

> The question of "widening" is not difficult.  Narrowing a buffer should
> not change the syntax of the characters in it.  Doing so leads to
> inconsistencies.

Yeah, you really want narrowing to be interpreted the way that is more 
convenient for your usage habits. I want it to be interpreted that's 
more convenient for the code I've written and ended up maintaining. 
Resolving this conflict requires some thought.

> If I understand correctly, the problem is that multiple-major-mode modes
> are trying to use narrowing to get a null syntactic context.  They are
> trying this because we don't provide anything better.  We should provide
> something better.  I suggested such a something last spring ("islands").

You suggested implementing a big, ambiguously defined feature.

We basically have no way to determine whether it would work out. I've 
spent some time on that discussion helping you narrow down the specs, 
but my personal takeaway is that it's too complex. Maybe I'm too 
unimaginative and lazy, though, so please go ahead and work on a 
prototype if you're confident.

In the meantime, however, we need to keep Emacs compatible with 
multiple-major-mode modes some other way.