Make it as clear as possible that RubyVM is MRI-specific and only exists on MRI

[eregon]

• See https://bugs.ruby-lang.org/issues/15743.
• Use "CRuby VM" instead of "Ruby VM" for clarity.

[k0kubun]

Why are you using both "MRI" and "CRuby"? How do you distinguish their usages?

[k0kubun]

Ah, "Ruby VM" -> "CRuby VM", but "MRI" by default. Maybe I understood.

[k0kubun]

I've heard of "MRI", "CRuby", and "Ruby VM", but I think I've never seen "CRuby VM".

While adding "MRI specific" descriptions looks good, I don't think it's a good idea to introduce a new confusing terminology "CRuby VM" to our source code as long as the similar terminology "Ruby VM" exists as a constant name RubyVM.

[eregon]

@k0kubun I used MRI for MRI specific because that's what existing documentation used.

Ruby VM is too ambiguous, I don't want to leave such ambiguity in the documentation (see https://bugs.ruby-lang.org/issues/15743 for more rationale).

I don't think it's a good idea to introduce a new confusing terminology "CRuby VM"

OK, let's try to find something else.
Why do you think it's confusing though?

Maybe for RubyVM::InstructionSequence, we should just use YARV since these are YARV bytecodes?
For other usages of CRuby VM, I can probably find other ways to say it.

[eregon]

@k0kubun I pushed 2 commits to avoid "CRuby VM", can you take a look? (I'll squash the commits when committing of course).

[eregon]

I dropped Ruby because it's clear from the function name, and just VM is used in other cases as well such as ruby_finalize and ruby_cleanup.

[k0kubun]

Why do you think it's confusing though?

The only concern I have is that the similar terminology "Ruby VM" exists.

So I would be completely fine with the original change b5e6a1d if RubyVM were renamed to CRubyVM and the old constant name RubyVM were removed after some deprecation period.

let's try to find something else.

TBH I don't have a strong preference on the naming of RubyVM constant itself. What I don't like is just inconsistency in terminology usages.

For describing "Ruby VM", a7111cb looks better.

I pushed 2 commits to avoid "CRuby VM", can you take a look?

In that sense, the current pull request (at bacf54d) looks good to me. Thank you for your attention to my comment :)

[k0kubun]

It seems to have a conflict now. Could you rebase this from master?

[k0kubun]

I fixed the conflict. Let's the current one and improve it afterwards as needed.