[Cython] Assignments in cdefs

[Dag Sverre Seljebotn]

Dag Sverre Seljebotn wrote:
> Stefan Behnel wrote:
>> Hi,
>>
>> Dag Sverre Seljebotn wrote:
>>> Stefan Behnel wrote:
>>>> What about code like this:
>>>>
>>>>     def test(a):
>>>>        cdef int c
>>>>        if a:
>>>>            c = 1
>>>>        if not a:
>>>>            c = 2
>>>>
>>>> How would you know what is a "first assignment" here? And what would you gain
>>>> from your ref-counting optimisation in this case?
>>> As for the example, it is a "best-effort" thing. If no assignments are 
>>> flagged as first, then the optimization just doesn't happen, which is 
>>> the likely outcome of your example.
>> Then what exactly is your "ref-counting optimisation" doing? Can you give me a
>> code example?
> 
> It makes "cdef int x = 3" behave as before, no more or less. Just 
> refactoring the code so that buffer worked. I needed to put the stuff 
> that handled the difference in refcounting somewhere, and that somewhere 
> leaves a hole in which to plug further improvements, so it was a natural 
> name, but it doesn't mean that it is more optimized than it used to be.
> 

Sorry! I meant

cdef MyExtensionsType a = x

(as int isn't refcounted...). Hmm, I guess that's where the confusion 
comes from; would tend to make everything I've said unintelligible.

-- 
Dag Sverre