[mike_hock]

GCC and Clang are open source, though, and Clang has a sane codebase, so why not implement it in an experimental fork of Clang?

[raydev]

I think you're underestimating the amount of work it takes to maintain a fork vs a separate transpiler layer.

Why waste time on forking clang when you can both hash out your language design and have a highly functional prototype right away?