Le 18 févr. 2012 00:58, "Charles R Harris" <charlesr.harris@gmail.com> a écrit :
>
>
>
> On Fri, Feb 17, 2012 at 4:44 PM, David Cournapeau <cournape@gmail.com> wrote:
>>
>> I don't think c++ has any significant advantage over c for high performance libraries. I am not convinced by the number of people argument either: it is not my experience that c++ is easier to maintain in a open source context, where the level of people is far from consistent. I doubt many people did not contribute to numoy because it is in c instead if c++. While this is somehow subjective, there are reasons that c is much more common than c++ in that context.
>
>
> I think C++ offers much better tools than C for the sort of things in Numpy. The compiler will take care of lots of things that now have to be hand crafted and I wouldn't be surprised to see the code size shrink by a significant factor.

There are two arguments here: that c code in numpy could be improved, and that c++ is the best way to do it. Nobody so far has argued against the first argument. i think there is a lot of space to improve things while still be in C.

You say that the compiler would take care of a lot of things: so far, the main thing that has been mentionned is raii. While it is certainly a useful concept, I find it ewtremely difficult to use correctly in real applications. Things that are simple to do on simple examples become really hard to deal with when features start to interact with each other (which is always in c++). Writing robust code that is exception safe with the stl requires a lot of knowledge. I don't have this knowledge. I have .o doubt Mark has this knowledge. Does anyone else on this list has ?

>>
>> I would much rather move most part to cython to solve subtle ref counting issues, typically.
>
>
> Not me, I'd rather write most stuff in C/C++ than Cython, C is cleaner ;) Cython good for the Python interface, but once past that barrier C is easier, and C++ has lots of useful things.
>>
>> The only way that i know of to have a stable and usable abi is to wrap the c++ code in c. Wrapping c++ libraries in python  has always been a pain in my experience. How are template or exceptions handled across languages ? it will also be a significant issue on windows with open source compilers.
>>
>> Interestingly, the api from clang exported to other languages is in c...
>
>
> The api isn't the same as the implementation language. I wouldn't prejudge these issues, but some indication of how they would be solved might be helpful.

I understand that api and inplementation language are not the same: you just quoted the part where I was mentioning it :)

Assuming a c++ inplementation with a c api, how will you deal with templates ? how will you deal with exception ? How will you deal with exception crossing dll/so between different compilers, which is a very common situation in our community ?

david

>
> <snip>
>
> Chuck
>
>
> _______________________________________________
> NumPy-Discussion mailing list
> NumPy-Discussion@scipy.org
> http://mail.scipy.org/mailman/listinfo/numpy-discussion
>