[Boost-users] Re: Re: result_of tutorial

16 Mar 2005

      Peter Dimov wrote:
...
Ian McCulloch wrote:
...
Peter Dimov wrote:
...
Mini-result_of-tutorial:
Q: What do I write in the space marked ??? below:
template ??? apply( F f, A1 & a1,
..., An & an )
{
    return f( a1, ..., an );
}
A:
typename result_of::type.
Is there any way to handle implicit conversions?
No, if I understand your question correctly. That is, from the caller's
point of view there is nothing to handle: you just pass the types of a1,
..., an to result_of. However writing the correct result_of specialization
for a function object that is not templated on its argument types, but has
two or more operator() overloads and relies on implicit conversions would
be a major pain.
Do you have a use case in mind?
Yes, if you want to forward to a function but you don't know if it takes
arguments by value or const reference.

I guess one could insist on using call_traits throughout, that is probably
good enough for my application.