[ruby-core:104173] [Ruby master Misc#17502] C vs Ruby

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Issue #17502 has been updated by Eregon (Benoit Daloze).


@ko1 Could you reply to this?

I feel C code in the middle of Ruby code is not so great, and if moving C code to strings in Ruby is just to add `Primitive.attr! 'inline'` (like for `Float#zero?`),
it seems much simpler and nicer to add `rb_impl_define_method_inline()` or so (private API, not public C API of course).

For instance, there is no syntax highlighting for C code in Ruby code (`Primitive.cexpr! 'flo_iszero(self) ? Qtrue : Qfalse'`), looking at callers of flo_iszero() would only reveal generated code, not the `Primitive.cexpr!`, etc.

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Misc #17502: C vs Ruby
https://bugs.ruby-lang.org/issues/17502#change-92350

* Author: marcandre (Marc-Andre Lafortune)
* Status: Open
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
----------------------------------------
Some features are coded in a mix of Ruby and C (e.g. ractor.rb).

External gems don't have access to this. The C-API to deal with keyword parameters is also very verbose the parsing and the engine does not know it.

Moreover, some optimization PRs are simply rewriting C-code into Ruby using pseudo C code.

I understand the intentions are great, but changes like https://github.com/ruby/ruby/pull/4018/files seem a symptom that something needs to be improved with the C api.

```diff
-static VALUE
- flo_zero_p(VALUE num)
- {
- return flo_iszero(num) ? Qtrue : Qfalse;
- }
# in different file:
+ def zero?
+ Primitive.attr! 'inline'
+ Primitive.cexpr! 'flo_iszero(self) ? Qtrue : Qfalse'
+ end
```

It seems to me that this is a way to circumvent a deeper issue. Is this the right direction?

Is there a plan for an API that would:
1) be accessible to C extensions
2) can't be re-written any faster in pseuso-C in Ruby
3) has an easy way to define keyword parameters?

I realize that RBS may give perfect signatures, but ideally `parameters` would be more informative for C-functions too.

```ruby
Ractor.method(:yield).parameters
# => [[:req, :obj], [:key, :move]] # good!
Fiber.method(:initialize).parameters
# => [[:rest]] # not good, should be [[:key, :blocking]]
```