Re: feature/tree-sitter: Where to Put C/C++ Stuff

[Eli Zaretskii <eliz@gnu.org>]

> From: Theodor Thornhill <theo@thornhill.no>
> Cc: emacs-devel@gnu.org, dev@rjt.dev, emacs-devel@gnu.org
> Date: Tue, 01 Nov 2022 12:53:11 +0100
> 
> > I also have hard time believing that you can reimplement those slow
> > parts of CC Mode to be much faster, but if you have code to show which
> > does that, I'm sure I'd be interested to look at it and consider
> > improving CC Mode using that code.
> >
> 
> You'd be surprised.
> 
> - https://github.com/emacs-csharp/csharp-mode/pull/251
> - https://github.com/emacs-csharp/csharp-mode/issues/207
> - https://github.com/emacs-csharp/csharp-mode/issues/164
> - https://debbugs.gnu.org/db/43/43631.html
> - https://github.com/emacs-csharp/csharp-mode/issues/151
> - https://github.com/emacs-csharp/csharp-mode/issues/200
> 
> All of these are solved with [0], no implementation needed for anything
> (apart from generic tree-sitter machinery of course). 

That's for C#, not for C/C++.

But if you can do the same for C/C++, sure, let's see the code and
judge its relative merits and demerits.

> >> 3: Confusion with where to file bugs
> >
> > Not relevant in our case: the bugs should be filed with Emacs.
> >
> 
> Well, are you sure?

You asked where to file the bugs.  The answer is: on debbugs.  If it
eventually turns out the bug is in tree-sitter, we will file a bug
there.  Just like we do with any other library we use.  Nothing new
here, IMO.

> >  . filling and breaking text in comments and strings
> >  . automatic insertion of newlines after braces, colons, commas, semi-colons
> >  . whitespace cleanups
> >  . minor modes: electric, hungry-delete, comment-style
> >  . c-offsets-alist and interactive indentation customization (related
> >    to indentation, but still extremely important, and not directly in
> >    tree-sitter)
> >
> 
> Yes, I've read the manual many times.  Filling is one nice thing,
> agreed.  electric, hungry-delete is just sitting there waiting for us to
> create a framework using tree-sitter that would benefit _all_ languages
> supported by tree-sitter, not just cc.

If tree-sitter can make these easier or faster or better, I see no
reason not to use tree-sitter for (some of) those features as well.
There's no decision to limit tree-sitter's use to fontification and
indentation, and I don't think we will ever make such decisions,
except if we have some bitter experience.

> > As they say, "show me the code".  If you can write up a C/C++ mode
> > from scratch which supports most everything in the CC Mode manual, do
> > it better/cleaner than CC Mode does, and do it before the emacs-29
> > branch is cut, in a month or so, I might change my mind.
> 
> Challenge accepted.  Can I create it for java, which is a language I'm
> writing a lot in these days?

Sorry, no.  It has to support all the languages supported by CC Mode
now.  That's the challenge.

It is fine by me to have a separate java-mode, but then I personally
will not be very interested in this, since editing the Emacs C code,
which I do a lot, will still need to use CC Mode.  Without decent
support for C/C++, CC Mode cannot be retired.

(Do people really use Emacs to develop Java?  I'd be surprised.)