Andy Little wrote:
"Jonathan Turkanis" <technews@kangaroologic.com> wrote
Andy Little wrote:
IOW the args are 'sugar' in the function pointer/ref case.
Hmmm ... interesting. That seems to be what TR1 says. Do you know why this is?
Not really....but the only useful data to result_of in the function pointer typedef is the return type, while in the case of function-objects the arguments are potent.
I realize this. I'm just saying that if someone has a unary function pointer type f and queries result_of<f(int, int)>::type she's probably making a mistake, and it would be useful for the compiler to let her know. (Of course the mistake will probably show up somewhere else too.)
IOW where T is a function-pointer, T describes it completely ; whereas where T is a function-object, the T(a,b,c) syntax is essential.
Therefore when T is a function-pointer, reference or straight function type result_of<T>::type would seem to me to be a valid invocation.
One of the main points (if not the main point) of result_of is to provide a uniform syntax, so you don't have to worry what sub category of callable objects you're dealing with.
regards Andy Little
Jonathan