Re: [Boost-users] Re: boost::bind and member functions

From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-03-22 16:35:37

David Morrison wrote:
> Peter Dimov wrote:
>
>> Change this to boost::mem_fn( f )( a1, a2, a3 ) and you'll be there.
>
> Yep, that's much cleaner, thanks.
>
> I was hoping that there'd be some clever way to use type_traits to
> magically select the right way of invoking the function f.  That way,
> one could have a (possibly enhanced version of?) apply.hpp so that
> code to invoke apply on a set of member and non-member functions
> would look the same.

On a reasonably conforming compiler, adding an overload to apply<> should 
work:

    template<class F, class A1, class A2, class A3>
        result_type operator()
        (F & f, A1 & a1, A2 & a2, A3 & a3) const
    {
        return f(a1, a2, a3);
    }

    // add this

    template<class M, class T, class A1, class A2, class A3>
        result_type operator()
        (M T::* pm, A1 & a1, A2 & a2, A3 & a3) const
    {
        return mem_fn(pm)(a1, a2, a3);
    }

It might be a good idea to add this to apply.hpp, but I would need to write 
a test for apply<> first.