[Cython] [cython] Initial startswith / endswith optimization (#35)

[John Ehresman]

On 5/26/11 3:27 AM, Stefan Behnel wrote:
>>> I think this means that the current unicode optimizations aren't used
>>> when
>>> variables are declared as str and a python 3 runtime is used. Should all
>>> unicode optimizations support str eventually?
>>
>> Yes.
>
> Well, minus those that are not portable. For example, the return type of
> indexing and iteration is the C type "Py_UCS4" for unicode, but the
> Python type "str" (i.e. bytes/unicode) for "str". I also didn't take a
> thorough look through the C-API functions for the str type in Py2 and
> Py3. Things certainly become more ugly when trying to optimise Python
> code into C for both platforms, than when leaving things at the Python
> type level.

Would it work for these methods to return Py_UCS4 in all 3 cases 
(unicode, bytes, str)?  In the bytes case, the multibyte int would 
simply be cast to char if that was what it was assigned to but the value 
wouldn't be above 255 in any case.

The case I worry about is losing optimizations w/ a Python3 runtime if 
str is used rather than unicode.

John