[zahlman]

Extremely cool. Thanks, GvR.

For my own language design I've wanted to introduce some of this ABC syntax back into Python. Mainly for unpacking data and doing index/slice assignments; a lot of beginners seem to get tripped up because assignments in Python use the same syntax as mutations, so maybe it's better to write e.g. `a['b'] = c` like `set b = c in a`, or `update a with {'b': c}`, or ... who knows, exactly.

[eru]

I agree that Python would benefit from separating mutation and assignment.

Especially when you are dealing with nested functions. You'd get around the whole need for 'global' and 'nonlocal' declarations. (Though your linter might still ask you for them for clarity.)

As a minimal syntax change, I would propose using perhaps = for introduction of a variable (the common case) and := for an explicit mutation of an existing variable.

But you could also use `let . = ..` and `. = ..` like Rust does.