Re: [boost] [intrusive] Review

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-03-20 13:47:44

AMDG

Sebastian Redl <sebastian.redl <at> getdesigned.at> writes:

> 
> Ion Gaztañaga wrote:
> > I mean:
> >
> > template<class T, member_hook T::* P>
> > class value_traits;
> >
> > compiles fine, but I just want to have one template parameter
> >
> > template<member_hook T::* P>
> > class value_traits;
> >
> > This is a compilation error. Can C++ deduce both the parent class and 
> > the pointer to member? I don't see any reason that should forbid this, 
> > but I can find the right syntax.
> >   
> There is none. There's no such thing as implicit template parameters.
> Each parameter must be explicitly specified.

It's possible but ugly using macros.

template<class MemberPointer, MemberPointer P>
class value_traits;

#define BOOST_INTRUSIVE_VALUE_TRAITS(member_pointer) \
    value_traits<BOOST_TYPEOF(member_pointer),member_pointer>

member_hook_t::BOOST_INTRUSIVE_VALUE_TRAITS(&T::hook)

In Christ,
Steven Watanabe