Re: [boost] Koenig lookup swap.

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-08-11 13:04:56

AMDG

David Abrahams <dave <at> boost-consulting.com> writes:

> >
> > template <class T>
> > void koenig_swap(T& left, T& right)
> > {
> >   using std::swap;
> >   swap(left,right);
> > }
> >
> > Several boost libraries (multi array, compressed pair, graph,
> > optional, spirit) already use this technique, each time explicitly
> > with 'using std::swap' instead of abstracting it out.
> 
> The appropriate name for that function is boost::swap
> 

To prevent infinite recursion or ambiguity we need:

namespace boost_swap_impl {

template<class T>
void swap_impl(T& left, T&, right) {
    using std::swap;
    swap(left, right);
}

}

namespace boost {

namespace swap_adl_barrier {

template<class T>
void swap(T& left, T& right) {
    ::boost_swap_impl::swap_impl(left, right);
}

}

using swap_adl_barrier::swap;

}

In Christ,
Steven Watanabe