Re: [boost] ConceptGCC 4.3.0 Alpha 6 is now available

From: Douglas Gregor (doug.gregor_at_[hidden])
Date: 2007-04-13 14:21:14

On Apr 13, 2007, at 3:24 PM, Daniel Walker wrote:

> On 4/12/07, Douglas Gregor <doug.gregor_at_[hidden]> wrote:
>> On Apr 12, 2007, at 12:16 AM, Mathias Gaunard wrote:
>>> Thank you.
>>> This is awesome.
>>>
>>> A version of GCC, and even precompiled binaries, with all those C+ 
>>> +0x
>>> features is a good thing as it will allow early usage and  
>>> spreading of
>>> those new features.
>>
>> The "OSL5" regression tester for Boost CVS HEAD tests a version of
>> GCC with all of those C++0x features *except* concepts, so we can
>> start (conditionally) using these features in Boost libraries.
>
> So, libraries could begin providing features that rely on decltype
> even if the features won't be available on all compilers, so long as
> the user has some way to conditionally include the features?

Yes. The Config library has macros for some C++0x features (e.g.,  
BOOST_HAS_RVALUE_REFS)

> I'm wondering if/when Boost can offer a result_of implementation using
> decltype along the lines of your suggested in N1454 (or typeof if
> reference preservation is not necessary). Perhaps, Boost.TR1 could
> provide a result_of that adheres to the current TR1 proposal and
> Boost.Utility could provide a decltype-based result_of.

The TR1 result_of is allowed to use compiler magic (read: decltype)  
to get the right answer, so yes, this is entirely possible and could  
probably be done now relatively easily.

        Cheers,
        Doug