Re: tree-sitter: conceptional problem solvable at Emacs' level?

[Theodor Thornhill <theo@thornhill.no>]

On 11 February 2023 09:22:06 CET, Konstantin Kharlamov <hi-angel@yandex.ru> wrote:
>On Sat, 2023-02-11 at 10:11 +0300, Konstantin Kharlamov wrote:
>> On Sat, 2023-02-11 at 07:51 +0100, Theodor Thornhill wrote:
>> > 
>> > 
>> > On 11 February 2023 07:36:26 CET, Konstantin Kharlamov <hi-angel@yandex.ru>
>> > wrote:
>> > > On Sat, 2023-02-11 at 09:25 +0300, Konstantin Kharlamov wrote:
>> > > > On Sat, 2023-02-11 at 10:17 +0800, Po Lu wrote:
>> > > > > Eli Zaretskii <eliz@gnu.org> writes:
>> > > > > 
>> > > > > > However, I meant the IDEs which are using tree-sitter and support
>> > > > > > developing C/C++ programs.  I believe some do.
>> > > > > 
>> > > > > I think most of those have similar problems supporting macros.
>> > > > > Who knows their names? I may be able to ask some of their users.
>> > > > 
>> > > > From my experience on and off work, there are just two IDEs (as in, not
>> > > > editors)
>> > > > used most widely for C++ code: QtCreator and Visual Studio. The first
>> > > > you
>> > > > discussed, the second is proprietary.
>> > > > 
>> > > > Then again, people most often code in C++ and C with text editors, in
>> > > > that
>> > > > case
>> > > > popular choices from my experience: Sublime Text and VS Code. These two
>> > > > have
>> > > > don't use tree-sitter either.
>> > > 
>> > > I installed Sublime Text on my Archlinux and tested with the C++ code OP
>> > > posted.
>> > > 
>> > > What I see is that ST does seem confused about indentation, while trying
>> > > to
>> > > make
>> > > a newline right after `slots:` line.
>> > > 
>> > > However, if you try to make a newline after the `void someSlot() {};`
>> > > line,
>> > > it
>> > > will use the indentation used on the previous line.
>> > > 
>> > > The default cc-mode in Emacs works similarly. The cc-ts-mode on the other
>> > > hand
>> > > doesn't make use of the previous indentation, and I think it should. It
>> > > would
>> > > resolve that problem and others, because in my experience it happens very
>> > > often
>> > > in C and C++ code that you want some custom indentation level, so you just
>> > > make
>> > > one and you expect the editor to keep it while creating more new lines.
>> > > 
>> > 
>> > That last statement sounds easily solvable. Can you send me a short example
>> > describing exactly what you want in a code snippet and I'll add it.
>> > 
>> > Thanks,
>> > Theo
>> 
>> Thank you! The example is below, but please wait a bit just to make sure
>> there's no opposition from other people, because I don't know if it works like
>> this on purpose, or not.
>> 
>> Given this C++ code with weird class members indentation:
>> 
>>     class Foo {
>>            int a;
>>            bool b;
>>     };
>> 
>> Now, suppose you put a caret after `bool b;` text and press Enter to make a
>> new
>> line (all tests are done with `emacs -Q`). The behaviour:
>> 
>> * cc-mode and Sublime Text: creates a newline with the indentation exactly as
>> on
>> the previous one.
>> * cc-ts-mode: re-indents the `bool b;` line, then creates a new one with a
>> custom indentation that is different from one on the `int a;` line.
>> 
>> The cc-mode and Sublime Text behaviour seems like less annoying to me, because
>> if I wanted to reindent the prev. line, most likely I'd did it by pressing an
>> indentation hotkey (e.g. `=` in Evil mode I use).
>
>Oh, wait, though I mistakengly used c-mode instead of c++-mode. The c-mode works this way, it keeps prev. indentation, however c++-mode instead uses a new indentation. It's odd they behave differently, and it certainly is different from other modes (e.g. emacs-lisp-mode). In this case I think the question of whether it should re-use prev. line indentation, which I think the should.

C-mode or c-ts-mode?

Yeah, this is what I'm thinking too. I'll look at it tonight or tomorrow :)

Theo