BNF available for mojo?

[chwmilcon]

With it understood that Mojo is a work in progress, is there a BNF available for the language as it is today? Or how it is imagined to be in the future? Pardon me if there's one already out there and I missed it.

[lattner]

We currently use a hand written parser in C++ and don't have a formal grammar unfortunately; we do have a black grammar, but it is "quite a superset" of the language. It would be great to build this out and document it.

[llllvvuu]

This would be very useful for tree-sitter-based applications.

[StandinKP]

Are we working on building the grammar for this? Would love to help out with it if that is in the bucket