[Python-ideas] Interrogate alternate namespace keyword and concept

[Steven D'Aprano]

On Fri, 14 Aug 2009 07:35:55 pm ilya wrote:
> Sorry, it's actually even easier; interrogate() is a one-liner:
>
> class Test:
>    '''Class to be interrogated.'''
>    def __init__(self, value):
>        self.value = value
>
> test = Test(10)
>
> def interrogate(what, how):
>    exec(how, what.__dict__)

Apart from the security implications of exec(), it also takes a fairly 
hefty performance hit. In Python 2.6:

>>> from timeit import Timer
>>> setup = 'from __main__ import test, interrogate'
>>> Timer("interrogate(test, 'value += 5')", setup).repeat()
[18.503479957580566, 18.218451023101807, 18.218581914901733]
>>> Timer("test.value += 5", setup).repeat()
[0.33056807518005371, 0.33118104934692383, 0.33114814758300781]

That's a factor of 55 times slower -- not precisely an optimization.



-- 
Steven D'Aprano