[Python-Dev] Possible optimization for LOAD_FAST ?

[Terry Reedy]

On 1/4/2011 6:39 PM, Guido van Rossum wrote:

> So, that significantly weakens the argument that this optimization
> will break unit tests, since I am happy to promise never to optimize
> these builtins, and any other builtins intended for I/O.

This is one comprehensible rule rather than a list of exceptions, so 
easier to remember. It has two rationales: such often need to be 
over-riden for testing, possibly in hidden ways; such are inherently 
'slow' so optimizing dict lookup away hardly makes sense.

-- 
Terry Jan Reedy