Re: [boost] Re: Re: Boost.Variant collaboration effort

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2002-07-21 10:37:02

From: "Itay Maman" <itay_maman_at_[hidden]>

> > I realize that poses some problems for unification, since it's not
> possible
> > to non-intrusively customize constructors for a single class template.
I'm
> > willing to discuss changes, if neccessary.
> >
> > -Dave
> >
>
> (i) Is it in the CVS?

Yes: boost/python/extract.hpp

> (ii) There's this MSVC namespace-related bug, which makes it impossible
to
> use extract<T>(x). The workaround I have used so far, is to pass T as a
> dummy parameter, i.e: extract(x, boost::type<T>());

The class formulation doesn't suffer from that, but there's also a
workaround for the function formulation...

> I wonder if there are other workarounds which will not affect the
interface
> of the function?

  template <class T, class U>
  whatever extract(variant<U> const&, boost::type<T>* = 0);

-Dave