Re: Extending define-derived-mode

[Yuan Fu]

> On Jun 2, 2023, at 4:54 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> From: Yuan Fu <casouri@gmail.com>
>> Date: Fri, 2 Jun 2023 00:50:07 -0700
>> Cc: Stefan Monnier <monnier@iro.umontreal.ca>,
>> emacs-devel@gnu.org,
>> mickey@masteringemacs.org,
>> theo@thornhill.no,
>> dgutov@yandex.ru
>> 
>>> It's a good point, indeed, but with some mode pairs is very hard
>>> (read: impossible) to achieve.  A notable example is c-mode and
>>> c-ts-mode: the former has a lot of mode-specific commands and features
>>> that cannot be used with the latter, because there's no equivalent
>>> infrastructure that supports the same interfaces, and sometimes
>>> because the feature makes no sense in a TS-based mode.  We try very
>>> hard to use the same key bindings and variable names where it does
>>> make sense, but the group of features where that is possible is very
>>> small.  For example, all the enormous set of features we have in CC
>>> mode around indentation and its customization cannot be "ported" to
>>> c-ts-mode and c++-ts-mode, because the latter is built on completely
>>> different analysis of the text.  Another example is the ad-hoc support
>>> for some frequently-use macro names that CC mode has.
>> 
>> I fully agree. Note thought that I wasn’t saying ts and non-ts modes should 
>> accept the same set of configs. I know all-too-well that’s impossible (for 
>> the majority of modes). I was saying that sometimes there are configs that 
>> can be shared (enabling electric-quote-local-mode, for example), and it 
>> would be nice to put them in a single hook rather than duplicating the code 
>> in two hooks. 
> 
> For users to be able to share stuff like electric-quote-local-mode
> we'd need to rewrite those supporting modes to allow that.  When one
> of the two modes uses regexps and syntax tables, whereas the other
> uses treesit-based parsers, this is not a trivial task.  I invite you
> to audit the various electric modes we have and see how many of them
> can be shared with minimum effort between non-TS and TS modes.

I’m talking about sharing the sharable config. Electric modes already work the 
same in ts and non-ts modes: electric-pair-mode and electric-quote-mode inserts 
matching pairs and quotes and aren’t affected by tree-sitter, 
electric-indent-mode uses the standard indent-line-function which both ts and 
non-ts modes confront to. Is there any other electric modes?

Also, ts modes generally have the same syntax table as non-ts modes. So if some 
package uses the syntax table they are largely not affected either.

Yuan