I don't think there's a limit in git. The structure might be a bit deep for git and thus some things might be unoptimized, but the shape is the same.
Tree.
This is an interesting idea for how to reuse more of git's infrastructure, but it wouldn't be backwards compatible in the traditional sense either. If you checked out the contents of that repo you'd get every node in the syntax tree as a file, and let's just say that syntax nodes as directories aren't going to be compatible with any existing tools.
But even if I wanted to embrace it I still think I'd hit problems with the assumptions baked into the `tree` object type in git. Directories use a fundamentally different model than syntax trees do. Directories tend to look like `<Parent><Child/></>` while syntax trees tend to look like `<Person> child: <Person /> </>`. There's no room in git's `tree` objects to put the extra information you need, and eventually the exercise would just start to feel like putting a square peg in a round hole.
Instead of learning that I should use exactly git's data structure to preserve compatibility, I think my learning should be that a successful structure needs to be well-suited to the purpose it is being used for.
But the git directory entry contains: * a type (this one is quite limited, so I'm not sure how well that could be (ab)used * a name * a pointer to the content
Which is exaclty what an AST entry has.
I'm sure you could abuse a git `tree` to squish in the extra data, but my point was just that you'd have to because a directory doesn't have a name that's separate from the name its parent uses to point to it. An AST node has both a name that its parent uses to point to it and an named identity e.g.:
``` <BinaryExpression> left: <Number '2' /> op: <'+'> right: <Number '2' /> </> ```
So my point is that to fit this into git you'd have to do something funky like make a folder called `left_Number`, and my question about this is the same question as I have in the first place about creating a folder on disk named `Number` whose contents are only the digit `2`. Since every existing tool will present the information as overwhelming amounts of nonsense compared to what users are used to seeing, has any compatibility at all been created? What was the point?
I also see the need to check out files as being an aspect of Git that relates purely to its integration with editors through flat text files. But if git was a more of a database than a filesystem then it's fair to assume that you'd prefer to integrate database access directly into the IDE.