[Python-ideas] breaking out of module execution

Tue Apr 24 22:38:14 CEST 2012

Georg Brandl wrote:
> On 24.04.2012 22:20, M.-A. Lemburg wrote:
>>>>> Think of code like this (let's assume the "break" statement is used
>>>> for stopping module execution):
>>>>>>>> """
>>>> #
>>>> # MyModule
>>>> #
>>>>>>>> ### Try using the fast variant
>>>>>>>> try:
>>>> from MyModule_C_Extension import *
>>>> except ImportError:
>>>> pass
>>>> else:
>>>> # Stop execution of the module code object right here
>>>> break
>>>>>>>> ### Ah, well, so go ahead with the slow version
>>>>>>>> import os, sys
>>>> from MyOtherPackage import foo, bar, baz
>>>>>>>> class MyClass:
>>>> ...
>>>>>>>> def MyFunc(a,b,c):
>>>> ...
>>>>>>>> def main():
>>>> ...
>>>>>>>> if __name__ == '__main__':
>>>> main()
>>>> """
>>>>>> There's a subtle bug here that shows that the proposed feature has its
>>> awkward points: you probably want to execute the "if __name__ == '__main__'"
>>> block in the C extension case as well.
>>>> No, you don't :-) If you would have wanted that to happen, you'd
>> put the "if __name__..." into the else: branch.
>> Not sure I understand. Your example code is flawed because it doesn't execute
> the main() for the C extension case. Of course you can duplicate the code in
> the else branch, but you didn't do it in the first place, which was the bug.

Ok, you got me :-) Should've paid more attention.
-- 
Marc-Andre Lemburg
eGenix.com
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