[C++-sig] Iterators for heterogeneous container

[Thomas Daniel]

I am having trouble wrapping a container that can hold multiple object 
types and therefore has multiple iterator types.

My C++ library has these classes:

class Tomato;
class Potato;
class Garden {
    Iter<Tomato>   get_tomatoes();
    Iter<Potato>   get_potatoes();
};

template<class T>
class Iter {
    T get_next();
};

which allows to write:

Iter<Potato> potatoes = garden.get_potatoes();
while (Potato potato = potatoes.get_next()) {
   cout << potato.name();
}

I am trying to use boost to wrap it so that I can write in python:

for potato in garden.get_potatoes():
   print potato.name()

Any pointers how to achieve this with boost?