Re: [Swig-user] Issues with -builtin

[Stefan Z. <sz...@gm...>]

On Sun, Jun 5, 2011 at 6:40 PM, Dieter Vandenbussche <
dva...@ax...> wrote:

Unfortunately, i ran into an issue trying to implement the rich
> comparison slot for one of the classes.  Hopefully, i'm not wasting your
> time with this stuff.
>

Not at all!  I spent a lot of time on the -builtin option, and I'm happy to
help.

Rich comparison is treated differently than other slots.  SWIG will always
generate a rich comparison routine which will dispatch to any C++ operator
overloads that are defined for a class.  For example, this:

%inline {
class Foo {
public:
    bool operator== (const Foo& x);
    bool operator< (const Foo& x);
};
}

... will cause SWIG to generate a rich comparison routine like this:

PyObject*
Foo_richcompare (PyObject *self, PyObject *other, int op) {
    switch (op) {
        case Py_EQ : // dispatch to Foo::operator==
        base Py_LT : // dispatch to Foo::operator<
        ...
    }
}


Stefan