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

[Konstantin Kharlamov <hi-angel@yandex.ru>]

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

Incidentally, I'm reading Stefan Monnier's paper presenting SMIE¹, and it has the
following example:

> […] It also means that the indentation code should strive to obey previous choices
> that the user made. For example if the user wants to indent its code in the
> following unconventional way:
>
>  longfunctionname(argument1, argument2,
>                      argument3,
>                      argument4);
>
> while the user should not be surprised if the auto-indenter tries to align
> ‘argument3’ with ‘argument1’, it would be reasonable for them to expect that
> ‘argument4’ stays put by simply aligning it with its nearest sibling rather than
> with the earlier ‘argument1’.

That is to say: yeah, the previous indentation level should be used by default if 
present.

1: https://arxiv.org/abs/2006.03103