[Cython] calling gmp automatically

[Ondrej Certik]

On Tue, Dec 23, 2008 at 2:46 PM, Dag Sverre Seljebotn
<dagss at student.matnat.uio.no> wrote:
> Ondrej Certik wrote:
>> Preferably one could use it like this:
>>
>> cdef mpz tmp
>> tmp = den/f.v[i]
>> vec[0][i] = f.v[i]*tmp
>>
>> or something like that and leave it to Cython to call the correct
>> methods. I don't like the fact that Cython would have to be gmp aware
>> --- maybe there is some way to just implement a cdef class mpz that
>> would support __add__, __mull__ and things like that, so as to behave
>> just like python integer, but still be as fast as the explicit code
>> above.
>
> Yep. Operator overloading using inline cdef functions should be a very
> non-controversial feature to add to Cython, and not very difficult to add
> either (transform from eg. BinopNode to SimpleCallNode in the right
> circumstances), and that would solve this problem in a much more generic
> way. At first that would require one to create a "cdef class" wrapper
> class containing the struct as a member and the overloaded operators, but
> when that is all working one could discuss allowing such overloads in
> structs as well?

Yes, I was thinking of something like this. How would this work technically?

cdef class mpz:
    cdef __cinit__(...)
        pass
    cdef inline __add__(a, b):
        cdef mpz tmp
        mpz_add(a.thisptr, b.thisptr, tmp)
        return tmp

So Cython would inline this.

Ondrej