[pygccxml-development] Proper overload resolution

[Benoit L. <ben...@mo...>]

Hello,

Consider the following class:

struct MyClass
{
void setBool(bool a);
void setInt(int a);
};

Because of the way the overloading resolution works currently in boost 
python, if you're trying to bind these two functions to __setitem__, 
only one of these functions (the last one bound actually) will always be 
called, no matter if you call __setitem__ with a bool or an int (for 
more information of the why, please take a look at the cplusplus-sig 
thread mentioned below).

The only way I could find to bind these two methods to __setitem__ and 
have them called "correctly" is to bind them as two separate functions, 
and then define a __setitem__ function in python at runtime, by adding 
something like that in the __init__.py file:

def custom_set_item(a):
  if isinstanceof(a, bool):
  ...
  ...

MyClass.__setitem__ = custom_set_item

Maybe there's a way to do that by binding a setitem which would take a 
bp::object and test the type in C++, I haven't tried.

It looks like Troy D. Straszheim came with a better implementation of 
the overloading mechanism (which is much closer to what we expect):
http://mail.python.org/pipermail/cplusplus-sig/2009-December/015047.html

It is apparently considered for addition in boost, but looks like 
they're waiting for the new langbinding integration:
http://www.boost.org/doc/libs/1_43_0/libs/python/todo.html

Any chance one of you have tried Troy's modification, or have any 
suggestion for this problem?

Thanks!
Benoit