"Mike Rovner" <mike@[...].com>  writes:

>  "Hugo van der Merwe" <hugo@[...].za> wrote in message
>  news:20021114053940.GB16542@[...]..
> > On Wed, Nov 13, 2002 at 08:19:53AM -0500, David Abrahams wrote:
> > > Hugo van der Merwe <hugo@[...].za> writes:
> > >
> > > Yes, but I'll leave it as an "exercise for the reader". Properties are
> > > a Python 2.2 thing, not a Boost.Python feature. Try it in pure
> > > Python. If you can get that to work, you can probably get it to work
> > > in Boost.Python. Hint: you'll need a proxy class.
> 
>  If I understand correctly
>  Pythons
>    x.a[3]=1
>  will go through
>  __setitem__(__getattr__(x,"a"), 3, 1)
> 
>  If so, it shall be easy (untested):
> 
>  struct proxy {
>    GetItem();
>    SetItem():
>  };
>  struct X {
>    proxy a;
>  }
> 
>  class_<proxy>("proxy")
>    .def("__getitem__", &proxy::GetItem)
>    .def("__setitem__", &proxy::SetItem)
>  ;
> 
>  class_<X>("X")
>    .add_property("a", &X::a)
>  ;
> 
>  Right?

No, object(&X::a) doesn't do anything useful (see the add_property
docs for why this is relevant).

    .def_readonly("a",&X::a)

would work, but I didn't think that was what you wanted. Did you
really want to modify your C++ X instance by adding a data member,
just to get the Python to work?

I had in mind:

proxy getter(X&) { return proxy(); }
...
 class_<X> ("X")
   .add_property("a", getter)
 ;


-- 
                       David Abrahams
   dave@[...].com * http://www.boost-consulting.com
Boost support, enhancements, training, and commercial distribution


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