Re: Missing features in c-ts-mode

[Ergus <spacibba@aol.com>]

On Fri, Feb 17, 2023 at 06:34:34PM +0100, Theodor Thornhill wrote:
>
>
>On 17 February 2023 17:37:47 CET, Ergus <spacibba@aol.com> wrote:
>>Hi Eli and Theo:
>>
>>Yes, I know that the feature is not very "popular" to be enabled by
>>default, but for parallel programming models based on pragmas (OpenMP,
>>OmpSs, OpenACC) it is very important.
>>
>>Many people in my previous work moved to some other editor after years
>>using emacs due to these apparently "small" details. Every time they
>>wanted to indent a portion of code (i.e they added an if around it), all
>>the pragmas moved out of their place and needed manual fix.
>>
>>On that moment I commented with Alan the possibility to make #pragma a
>>syntactc symbol which we could control its indentation like anything
>>else in c-mode (with +, ++, -, 0 or [0]). But he said that it required
>>too many changes to implement that and offered this "toggle" solution
>>good enough for me.
>>
>>I will open the feature request in a moment, but just wanted to comment
>>the alternative solution more consistent and without an extra mode;
>>because maybe that way may be simpler now in the new mode??
>>
>>Best,
>>Ergus
>>
>>On Fri, Feb 17, 2023 at 02:20:59PM +0200, Eli Zaretskii wrote:
>>>> From: Theodor Thornhill <theo@thornhill.no>
>>>> Cc: Eli Zaretskii <eliz@gnu.org>, casouri@gmail.com, emacs-devel@gnu.org
>>>> Date: Fri, 17 Feb 2023 10:56:28 +0100
>>>>
>>>> >      #pragma parallel for first private(x) \
>>>> >          shared(y) etc
>>>> >      for (...) {
>>>> >          ....
>>>> >      }
>>>> > }
>>>> >
>>>> > In this case the pragma in column zero is very confusing. Alan added a
>>>> > new mode (c-toggle-cpp-indent-to-body) which worked around this issue a
>>>> > few years ago. I don't if it is possible to enable similar behavior with
>>>> > your change? Is is?
>>>> >
>>>> > Best,
>>>> > Ergus
>>>> >
>>>>
>>>> It's absolutely possible, but IMO that sounds like an improvement for
>>>> emacs 30, maybe?
>>>
>>> It depends on how simple and safe the change will be.  But yes, I'm
>>> okay with delaying this to Emacs 30 if the addition is complex enough.
>>>
>>> Thanks.
>>>
>
>Would this mean you'd want all preproc directives configurable, or only
>some in particular? I think a defcustom for either/or is doable for
>Emacs 29, but for granular control we'd need to think a bit more.
>
>c-ts-mode-preproc-indent-to-body?


Hi Theo:

AFAIK only #pragmas have this behavior, so I think a custom for #pragmas
may be enough if the alternative becomes complex or complicated.

I commented the initial problem as it was just in case tree-sitter
already have all the spices to go for the general solution in a
"simpler" way, with a consistent syntax and without an extra
defcustom/toggle-mode.

Maybe there is a point in between like treat #pragmas as a different
kind of directive than preproc (which they actually are BTW, #pragmas
are not exactly preprocesor directives, but hints for the compiler
itself).

In that case the user could write something more or less like:
  ((node-is "pragma") parent 1)
  ((node-is "pragma") no-indent)

in the indent-style.

WDYT?