Scoping loops (was Re: Feature request: subclassing FunctionType)
Aahz
aahz at pythoncraft.com
Tue Mar 2 05:55:42 EST 2004
In article <95aa1afa.0403012224.506dd07c at posting.google.com>,
Michele Simionato <michele.simionato at poste.it> wrote:
>
>1. Assuming all "for" loops and list comprehensions are replaced
> with Haskell bindings rules, what about backward compatibility
> problems? For instance: is there enough code relying on the loop
> variable being available outside the loop?
Yes. Guido has Pronounced that this will stay, but...
>2. If, due to compatibility issues, it is not possible to change the
> binding rules of existing loops, would it make sense to propose
> these binding rules for Python 2.4 generator comprehension?
> This would not be backward incompatible, but would it generate
> confusion?
....while the rules for generator expressions have not been finalized,
Guido has agreed that they will have their own scope and that listcomps
will be changed in Python 3 to have their own scope. You should read the
python-dev thread on generator expressions yourself to understand what's
being proposed.
--
Aahz (aahz at pythoncraft.com) <*> http://www.pythoncraft.com/
"Do not taunt happy fun for loops. Do not change lists you are looping over."
--Remco Gerlich, comp.lang.python
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