[Python-Dev] assignment expressions: an alternative proposal (original) (raw)

Yury Selivanov yselivanov.ml at gmail.com
Tue Apr 24 11:46:57 EDT 2018

On Tue, Apr 24, 2018 at 11:28 AM, Chris Angelico <rosuav at gmail.com> wrote:

On re-thinking this, I think the distinction IS possible, but (a) only in function/class scope, not at global; and (b) would be defined in terms of lexical position, not run-time. For instance:

def f(): (a = 1) # Legal; 'a' has not been used yet a = 2 # doesn't change that def f(a): (a = 1) # Invalid - 'a' has been used already def f(): while (a = getnext()): # Legal ...

Now this is a weird rule. Moving functions around files would become impossible.

Please experiment with my reference implementation, it already implements my proposal in full. Loops and inline assignments work as expected in it.

Yury

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