[Python-Dev] Informal educator feedback on PEP 572 (was Re: 2018 Python Language Summit coverage, last part)

[Greg Ewing]

Nick Coghlan wrote:
> actually made those semantics available as an explicit
> "parentlocal NAME" declaration ...:
> 
>     def _list_comp(_outermost_iter):
>         parentlocal item
>         _result = []
>         for x in _outermost_iter:
>             item = x
>             _result.append(x)
>         return _result
> 
>     _expr_result = _list_comp(items)

I'm not sure that's possible. If I understand correctly,
part of the definition of "parent local" is that "parent"
refers to the nearest enclosing *non-comprehension* scope,
to give the expected result for nested comprehensions.
If that's so, then it's impossible to fully decouple its
definition from comprehensions.

-- 
Greg