I am writing a c type extension for Python deriving from the list class (using
PyList_Type.tp_init). I have the need to overload the + operator (To add two
numbers stored as binary lists instead of concatenation). I have tried the
following:
static PyMethodDef BinaryList_methods[] = {
...
{"__add__", (PyCFunction)BinaryList___add__, METH_VARARGS,
PyDoc_STR("__add__(self,other) -> BinaryList")},
...
{NULL, NULL},
};
This the BinaryList___add__ function is called if I use the __add__ explicitly
but the list base class __add__ is called for the + operator, for example:
a = BinaryList([1,0,0,0])
b = BinaryList([0,0,0,1])
print a.__add__(b) #prints [1,0,0,1]
print a + b #prints [1,0,0,0,0,0,0,1]
I read this:
object.h -- Added tp_call member to the typeobject struct
This along with a minor change to the ceval.c allows overloading
of the function call operator for any class.
Can anyone either tell me what I am doing wrong and or give me an example of
how to properly overload an operator in a c coded extension?
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
