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

From: Anthony Williams (anthony_w.geo_at_[hidden])
Date: 2008-04-07 13:11:11

"Peter Dimov" <pdimov_at_[hidden]> writes:

> Anthony Williams:
>> "Peter Dimov" <pdimov_at_[hidden]> writes:
>>
>>> Eric Niebler:
>>>
>>>> Can you write what the identity function object would look like in 
>>>> C++0x?
>>>
>>> struct identity
>>> {
>>>     template<class A> A operator()( A && a ) const
>>>     {
>>>         return std::forward<A>( a );
>>>     }
>>> };
>>>
>>> I guess.
>>
>> No. That will convert lvalues to rvalues.
>
> Try it. 

I have, and it doesn't work. Besides, you can see in the signature: it returns
"A" by value.

You either need the overloads, or you need a trait class to correctly
determine whether to return A or A&.

Anthony
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