Rewrite and simplification of Chalk core

[srush]

I was reading about some of the more recent updates to the Python type system and thought I would try a new version of the chalk core that fixed things that bothered me. This is a rather big PR, but most of it is pretty simple.

Changes:

• Changed the Compose node to have a list of children instead of 2.
• Changed + to merge to the list instead of adding to the tree when possible.
• Added a Monoid "typeclass" with a default + and empty, and a general concat. Nearly everything in chalk is a monoid now
• Added a Maybe / MList to make these monoid'able.
• Make Visitor define an explicit generic argument for its down / up elements. Default behavior is that the down element is a monoid and define default behavoirs for compose, empty, etc. Remove kwargs hack.
• Replace fake placeholder TTrans types with new Self argument.
• Remove repeated Abstract class / Interface overlaps. (this is probably incorrect, but it makes the code simpler)

Issues:

• Currently it works with python 3.10+. Need to try with earlier versions.

Why?

• Reason 1 - cleaner types and less code to simplify things.
• Reason 2 - I've been playing around with this library Penzai that includes a really nice tree visualizer. with a couple of lines of code you can view the whole tree from Chalk when you draw. It's pretty slick.

https://chalk-diagrams.github.io/viz/

[danoneata]

Thank you, Sasha! I'll take a closer look at the PR in the next couple of days (on Thursday probably). The penzai visualization looks sleek! I think it can be really useful for debugging!

[danoneata]

• Make Visitor define an explicit generic argument for its down / up elements.

Nice; I like that we now have the input type explicitly specified for the visit methods!

Default behavior is that the down element is a monoid and define default behavoirs for compose, empty, etc.

I was curious: for the ToSVG visitor, the return type is svgwrite.base.BaseElement; how does that the type system know that this is a Monoid?

By the way, how do you type check code? Are you still using mypy? Which version and which options?

[srush]

• Oh the BaseElement thing might be a bug. I think MyPy doesn't have the stubs for svgwrite and so it is likely failing to check that.

• I am using mypy 1.10, should we switch to pyright?

[danoneata]

Thanks for the pull request and merge!

I am using mypy 1.10, should we switch to pyright?

Hmm... I don't have a strong opinion towards one or the other. But I see that pyright reports a few errors on our codebase (although I expect these to be fixable).

[srush]

K, I think I'll fix these, bump the required version to 3.10+, update the docs, and then up the version number. Excited to check out the animation lib as well.