Re: [boost] 'function' idea

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-11-09 20:07:08

On Saturday 09 November 2002 07:21 pm, Aleksey Gurtovoy wrote:
[snip some code...]
>     template< typename T > yes_tag is_callable_helper(
>           sink< sizeof(&T::operator()) >*
>         );
[snip more code...]

Won't work if there are multiple overloads of operator() or if it is a 
function template, unfortunately :(

> But of course none of the compilers are particularly happy about it. How
> about adding 'is_callable<>' to the type_traits proposal and requesting a
> compiler support for it?

We could, but I have a hunch that we wouldn't get it. The is_callable trait 
takes a lot of specification and only handles very specific cases. If we're 
going to ask for something like is_callable, we're better off asking for 
something that handles more cases (i.e., "is this expression valid?" or "can 
I instantiate this class template?").

        Doug