[Python-Dev] Simple Switch statement

Mon Jun 26 02:46:46 CEST 2006

At 01:37 PM 6/25/2006 -0700, Raymond Hettinger wrote:
>>>No thanks. That is its own can of worms. The obvious solutions (like const
>>>declarations, macros, or a syntax to force compile-time expression 
>>>evaluation)
>>>are unlikely to sit well because they run afoul Python's deeply ingrained
>>>dynamism.
>>>>>>>I think perhaps you haven't been paying close attention to Fredrik's 
>>proposal.
>Yes, I have been. That is one of the three options I listed above.
>Each has its own issues.
>>The static() keyword works like Forth's brackets for forcing compile-time 
>evaluation.

No, it doesn't; this is why I suggested that you haven't been paying close 
attention. The evaluation is at function definition time, not compile time.
>The issue for us is that unlike other Python expressions, there are 
>inconvenient limitiations on what can be expressed inside:
>> five = 5
> eight = [8]
> def f(x, six=6):
> seven = 7
> a = static(five + 4) # this is legal
> b = static(six + 4) # this is illegal
> c = static(seven + 4) # this is illegal
> d = static(eight + [4]) # this is illegal

The last one is perfectly legal, and the middle two make no sense.