So, this uses a macro, but if you’re thinking anything is possible with a macro, it’s actually not in Rust. The input does still need to parse as valid Rust tokens.
Which means the authors asked themselves at some point: Is the Rust syntax a superset of the Python syntax?
And well, it’s not. In particular, some Python keywords will just be tokenized as an identifier (like a variable name).
But it is close enough that the authors decided against requiring a massive string to be passed in, which does amuse me. 🙃
With projects like these, I’m always torn between thinking that it’s cool it’s possible, and horror that someone somewhere will try to use this in production code.