Baby L4 -- a precursor to Natural L4

In 2020/2021, first came the BNFC-based L4 https://github.com/smucclaw/dsl/tree/main/bnfc

In 2021/2022, we tried to separate out a core language. We called it core-l4, or baby-l4. That effort is recorded at https://github.com/smucclaw/baby-l4

In 2022/2023, we brought up the natural4 toolchain.

In 2024 we started thinking about going back to basics with a BNF-based grammar again.