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[Python-Dev] Please reject or postpone PEP 526

Ian Foote ian at feete.org
Mon Sep 5 12:51:47 EDT 2016 
On 05/09/16 14:46, Nick Coghlan wrote:
> That's not what the PEP proposes for uninitialised variables though:
> it proposes processing them *before* a series of assignment
> statements, which *only makes sense* if you plan to use them to
> constrain those assignments in some way.
> 
> If you wanted to write something like that under a type assertion
> spelling, then you could enlist the aid of the "all" builtin:
> 
>     assert all(x) : List[T] # All local assignments to "x" must abide
> by this constraint
>     if case1:
>         x = ...
>     elif case2:
>         x = ...
>     else:
>         x = ...
> 

Would the `assert all(x)` be executed at runtime as well or would this
be syntax only for type checkers? I think this particular spelling at
least is potentially confusing.

Regards,
Ian F

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