Re: [boost] [type_traits] any interest in integral_promotion?

From: Andy Little (andy_at_[hidden])
Date: 2005-06-22 14:13:10

"Alexander Nasonov" <alnsn-boost_at_[hidden]> wrote in message 
news:loom.20050622T171035-650_at_post.gmane.org...
> Andy Little <andy <at> servocomm.freeserve.co.uk> writes:
>
>> Isnt any use case for this covered by  Boost.Typeof ?
>
> Quote from Boost.Typeof documentation:
>
> Other integral types, such as *enums*, need to be described explicitly with 
> the
> BOOST_TYPEOF_INTEGRAL macro, like (BOOST_TYPEOF_INTEGRAL(MyEnum))

I think that applies when the type of the enum is taken, but  where required 
enums are promoted to some integer type,dependent on numeric value.
In what other situation is promotion required?

#define BOOST_TYPEOF_COMPLIANT
#include <boost/typeof/typeof.hpp>
#include <iostream>

struct X{
    enum id{x,y};
};

int main()
{
    BOOST_AUTO( result , X::x + X::y);
    std::cout << typeid(result).name() <<'\n';
}

Andy Little