[Cython] __add__ type declaration

[Benjamin Peterson]

Hi!

For fun, I have been implementing a Python binding to GMP. I have a class like
this:

cdef class GMPInt:

    cdef mpz_t ob_val
    ....
    def __add__(self, GMPInt other):
        cdef mpz_t temp
        mpz_init(temp)
        mpz_add(temp, self.ob_val, other.ob_val)
        mpz_clear(temp)
        ....

When I try to compile it I get this error:

        mpz_add(temp, self.ob_val, other.ob_val)
                         ^
------------------------------------------------------------

/temp/sandbox/pygmp/src/_gmp.pyx:49:27: Cannot convert Python object to 'mpz_t'


It compiles correctly when I define a declaration for self in __add__
like this, though:

def __add__(GMPInt self, GMPInt other)

I thought type declarations were supposed to be implicit on self in
classes. Is this just an anomaly?

I have Cython 0.10.

Thanks for the help!
-- 
Cheers,
Benjamin Peterson
"There's nothing quite as beautiful as an oboe... except a chicken
stuck in a vacuum cleaner."