Re: [Boost-users] [mpl] newbie question

From: Andy Little (andy_at_[hidden])
Date: 2006-02-24 09:06:34

"Peter Dimov" <pdimov_at_[hidden]> wrote in message
news:000c01c63940$5b10b6b0$6407a8c0_at_pdimov2...
> David Abrahams wrote:
>> "Andy Little" <andy_at_[hidden]> writes:
>>
>>> "David Abrahams" writes
>>>
>>>> The result of the transform is only required to be
>>>> "concept-identical" to the result you're looking for.
>>>
>>> IMO that behaviour is sloppy. I see no reason why (at least)
>>>
>>> boost::is_same < plus< int_<1> ,int_<1> >::type, int_<2> > shouldnt
>>> be true.
>>
>> Patches welcome, and all that.  If you can figure out how to do it
>> without greatly complicating the library, I'm sure Aleksey would be
>> glad to adopt your code.
>
> I'd question this decision. Code that assumes that plus< int_<1>, int_<2>
> >::type is int_<3> is by definition more limited than code that handles any
> result as long as its ::value is 3.

int_<1> and int_<2> are types not concepts. What other type can *more
advantageously* be returned here bearing in mind that currently I get an
integral_c<int,N>  back?

regards
Andy Little