Re: [PATCH] fix delete-property handling

[Ikumi Keita]

Hi Artem,

>>>>> Artem Yurchenko <artemyurchenko@zoho.com> writes:
> Suppose that TeX-electric-math is set to dollar and
> TeX-refuse-unmatched-dollar is set to true. I am thinking, when is the
> «refuse the dollar» behaviour going to happen? It's not going to
> happen in inline math or display math — the user uses dollars for math
> and we never «refuse the dollar» when enclosed by dollars. It's /only/
> going to apply in some environments that don't explicitly use dollars,
> such as «equation», «align», «cases*» and so on. However, in some of
> those environments this behaviour is going to be /incorrect/, as noted
> in bug#57626, for example.

> So, the only environment (sorry for the pun) where we «refuse the
> dollar» is also the environment where that feature breaks
> occasionally.

Thanks, now I see what you mean. I naively imagine that users (if exist
at all) who like such customization would happily type C-q $ when they
encounter such refusal. Anyway, I think this topic isn't much important.

>> I think other occurrence of single quotes in

>>> you need exactly one $, you can use `C-1 $'.

> I think I should use `C-1 \\[TeX-insert-dollar]' according to the help
> entry on «Keys in Documentation»?

I'm talking about single quotes surrounding the key sequence. ...Hm, I
was thinking that elisp reference discourages to surround key sequence
by single quotes, but it seems that's my hasty conclusion. Sorry, forget
about this.

>>> Otherwise, when in a verbatim construct or escaped with `\\',
> >should also fixed according to the elisp reference direction.
> Oh, yes, missed that.

By the same argument, I withdraw this remark as well.

> I had an impression that it should blink to the closing paren when
> applied to a region in the electric mode, but per docs it's not
> required. However, it doesn't respect the behaviour of
> blink-matching-paren, which allows the user to choose between jumping
> onscreen, jumping offscreen or just blinking.

Thanks for clarification. I don't think blinking is needed when there is
an active region because the starting position is obvious without
blinking. On the other hand, I realize that `TeX-insert-dollar' falls
much behind at emulating emacs built-in paren-matching behavior.
Well, it seems to me that poor blinking feature isn't a serious issue,
so my opinion is to postpone it for now. :-)

>> I noticed two incompatibilities with the current behavior.
> Okay, I guess it is more difficult than I felt initially :D

:-)

>> 2. Suppose that TeX-electric-math is a pair of dollars. Then typing $
>> at
>> $E = mc^2-!-
>> inserts two dollars, not one dollar.

> That is indeed a regression, however, I feel that it might be not very
> serious. An electric user will almost always have balanced dollars.

Unbalanced dollar often occurs during editing drafts and revising
existing documents even for an electric user. Thus I think this behavior
must be fixed.

>> (This is optional) The revised patch increases calls to `texmathp'. It
>> doesn't make much difference anyway, it is preferable if you can reduce
>> them.

> Will consider the best approach to this. My first idea is actually to
> «cache» texmathp. That is, when we see that the buffer is unmodified
> since the last call, we just don't do anything.

I think it's enough to cache in one command execution. When the user
types "$", `texmathp' is called once in `TeX-insert-dollar-refuse-p' and
again at
----------------------------------------------------------------------
   ((and (texmathp)
         (or (string= (car texmathp-why) "\$")
             (string= (car texmathp-why) "\$\$")))
----------------------------------------------------------------------
in the body of `TeX-insert-dollar', in your last patch. I'm not sure
whether you plan to keep the basic logic structure of electricity, but
if it is kept, the first result of `texmathp' can be used for the
second. (There is another call in `delete-selection' property which
calls `TeX-insert-dollar-refuse-p', but it seems difficult to me to make
use of cache in a simple and robust way.)

Regards,
Ikumi Keita
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