Re: [boost] boost::result_of and C++03

From: Eric Niebler (eric_at_[hidden])
Date: 2008-04-09 20:34:15

shunsuke wrote:
> shunsuke wrote:
>> Eric Niebler wrote:
>>> I think that's right so far. Now imagine a simple identity function 
>>> object, that just returns its argument unmodified:
>>>
>>> struct identity
>>> {
>>>    template<typename Sig>
>>>    struct result;
>>>
>>>    template<typename This, typename Arg>
>>>    struct result<This(Arg)>
>>>    {
>>>      typedef Arg type;
>>>    };
>>>
>>>    template<typename Arg>
>>>    Arg const &operator()(Arg const &arg)
>>>    {
>>>      return arg;
>>>    }
>>>
>>>    // and a non-const overload, too
>>> };
>> Let me clarify.
>> This identity implementation is simply wrong (if you pass an rvalue to identity.)
>> because of inconsistency between decltype and result_of.
> 
> Ditto that tr1_function.
> Am I right?

I don't think you are right, at least not for C++03. There is no 
decltype, so there can be no inconsistency with it. :-) Do you still 
think that the tr1_function wrapper I sent around is wrong, and if so, why?

-- 
Eric Niebler
Boost Consulting
www.boost-consulting.com