[Python-Dev] Possible optimization for LOAD_FAST ?
lukas.lueg at googlemail.com
Tue Jan 4 23:13:19 CET 2011
I very much like the fact that python has *very* little black magic
revealed to the user. Strong -1 on optimizing picked builtins in a
2011/1/4 Steven D'Aprano <steve at pearwood.info>:
> Guido van Rossum wrote:
>> On Tue, Jan 4, 2011 at 2:49 AM, Michael Foord <fuzzyman at voidspace.org.uk>
>>> I think someone else pointed this out, but replacing builtins externally
>>> a module is actually common for testing. In particular replacing the open
>>> function, but also other builtins, is often done temporarily to replace
>>> with a mock. It seems like this optimisation would break those tests.
>> Hm, I already suggested to make an exception for open, (and one should
>> be added for __import__) but if this is done for other builtins that
>> is indeed a problem. Can you point to example code doing this?
> I've been known to monkey-patch builtins in the interactive interpreter and
> in test code. One example that comes to mind is that I had some
> over-complicated recursive while loop (!), and I wanted to work out the Big
> Oh behaviour so I knew exactly how horrible it was. Working it out from
> first principles was too hard, so I cheated: I knew each iteration called
> len() exactly once, so I monkey-patched len() to count how many times it was
> called. Problem solved.
> I also have a statistics package that has its own version of sum, and I rely
> on calls to sum() from within the package picking up my version rather than
> the builtin one.
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