bpo-40939: Remove the old parser (Part 2)

[lysnikolaou]

https://bugs.python.org/issue40939

[gvanrossum]

LG assuming the tests pass.

[nnemkin]

PyParser_ASTFromXXX functions are public API that don't depend on the parser internals. Why are they being removed? Seems like a pointless compatibility break.

[bedevere-bot]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[lysnikolaou]

I have made the requested changes; please review again

[bedevere-bot]

Thanks for making the requested changes!

@gvanrossum, @pablogsal: please review the changes made to this pull request.

[pablogsal]

LGTM

[pablogsal]

@lysnikolaou I was going to start a PR for re-implementing/re-naming the parser functions but maybe you have already started one? :)

[lysnikolaou]

@lysnikolaou I was going to start a PR for re-implementing/re-naming the parser functions but maybe you have already started one? :)

I was just about to, but you can do it if you think reviewing my PR is going to take more time. Whatever you want!

[pablogsal]

I was just about to, but you can do it if you think reviewing my PR is going to take more time. Whatever you want!

Go ahead if you have time now, as I will only be able to do one in a couple of hours

[gvanrossum]

Agreed that the public APIs that don't depend on types like mod_ty from the old parser should stay. I think they should not become macros -- they should stay real functions that just call the Pegen functions. (I don't like the "pegen" name leaking into public APIs.)