Re: [Boost-users] Re: Functors and function_traits<>

From: Hossein Haeri (powerprogman_at_[hidden])
Date: 2004-12-29 06:34:25

Dave,

> >> > AFAIK, std::iterator_traits<> is one of the
> >> > counterparts of function_traits<>, not?
> >> > 
> >> > A sort of symmetry which iterator_traits<> has
> got
> >> is
> >> > that it can work for Iterators as well as plain
> >> > pointers. 
> >> 
> >> That's the wrong way to think about it.  It just
> >> works for iterators.
> >> Plain pointers just happen to be iterators, by
> the
> >> *standard's
> >> definition* of "iterator."
> > 
> > Smart Alec... ;) Alright I could be more specific
> > speaking like this: 
> > 
> > "... it can work for Iterators which happen to be
> > classes as well as plain pointers."
> > 
> > Excused me? :)
> 
> I'm not just being pedantic.  It's hard to explain
> why function_traits
> is the way it is without making that distinction.
> 
> >> > This seems to be not the case for
> >> function_traits<>.
> >> > That is, you can pass a function type to it,
> but
> >> you
> >> > can't do that for a functor. Is that right?
> >> 
> >> That's because function object types (what you're
> >> calling functors)
> > 
> > It's not me, AFAIK. That's another common name of
> > them. Isn't that?
> 
> Yes, but it's frowned upon by many because it's a
> completely invented
> meaning for a term that already had a
> well-established meaning in
> mathematics and computing.  If you read Stroustrup
> or almost any other
> author who's also on the committee you'll see the
> term "function object"
> and not "functor."

I see. :)

All of the Best,
--Hossein

                
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