Using cython .pxd files to Augment pure python files

Question

Following the example here, "Augementing .pxd", I'm trying to use ".pxd" files to augment a pure python file. (Add type definitions external to the pure python file).

python file:

class A(object):
    def foo(self, i=3, x=None):
        print "Big" if i > 1000 else "Small"

pxd file:

cdef class A:
    cpdef foo(self, int i, x)

I've got a dictionary, which I'm defaulting to "None" in python. Unfortunately, cython doesn't like this.

If I use my "pure" python file, without declaring a type or declare the type as "dict" in the pxd file I get the error:

"Signature not compatible with previous declaration"

I noticed that it will compile if I do NOT specify a default value, but there's a reason for declaring the defaults.

Is there a way this can be handled?

Answer 1

Optional arguments in cpdef functions are declared differently from cdef functions which essentially is same as python functions.

Your .pxd file should be modified to be written as

cdef class A:
    cpdef foo(self, int i=*, x=*)