[C++-sig] Re: Re: Re: custom iterator object

[Mike Rovner]

> Well, you can't use range(...) here; that's intended for real C++
> iterators, and you don't have any (PyIter doesn't conform).

(Aside question) Why?
To put it another way, how to write a conforming or use an iterator_adaptor?
I was convinced that that way will be more clear and maintainable.

> Here's my suggestion:
>
>   Try doing what you need to do in Pure Python. Build a little
>   new-style class (derived from object) called Scheme, and add the
>   iterator interface you want to see. To do that, you may find
>   yourself building some little Python iterator classes.

Like that:

class Iter:
  def __init__(self,a): self.a=a()
  def __iter__(self): return self
  def next(self): return self.a

class Scheme:
  def __iter__(self): return Iter(self.A)
  def i2(self): return Iter(self.B)
  def i3(self): return Iter(self.C)
  def A(self): return 1
  def B(self): return 2
  def C(self): return 3

>   Now, when you have all that working, translate your Python iterator
>   classes into C++, and wrap them with Boost.Python. Remember that the

Python code above working but I still have problems with C++:
How can I pass 'this' from wrapping class?

PyIter make_iter(const Scheme* s, GetFunc f) { return s->(*f)(); }
...
 class_<Scheme>("Scheme")
    .def("__iter__",  make_iter(this,&Scheme::A))
    .add_property("b", make_iter(this,&Scheme::B))
    .add_property("c", make_iter(this,&Scheme::C))
    ;

Mike