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. 🙃

  • EpheraOP
    13·
    3 months ago

    From what I understand, it works like this:

    1. Rust compiler reads the pseudo-Python and tokenizes it according to Rust’s rules.
    2. Macro code converts the tokens back to (now proper) Python, while filling in the captured variables. I believe, this is the code that does this.
    3. Python code is executed in an actual Python interpreter, via PyO3.