Re: [boost] units: review

From: Steven Watanabe (steven_at_[hidden])
Date: 2007-03-29 13:44:57

AMDG

Lewis Hyatt <lhyatt <at> princeton.edu> writes:

> The only problem with that is it would require a separate check for all 
> different types of units in use, even though each check was conceptually 
> doing the same thing.
> 
> I guess it would be a simple matter for the user to derive a new 
> template from quanity<Q,T> for the sole purpose of adding the static 
> assert, so perhaps the library itself doesn't need to be concerned with 
> this.

How about:

template<class T, class Unit, class Y>
T technically_nonportable_quantity_cast(quantity<Unit, Y>& q) {
    BOOST_STATIC_ASSERT(sizeof(quantity<Unit, Y>) == sizeof(T));
    return(reinterpret_cast<T>(q));
}

template<class T, class Unit, class Y>
T technically_nonportable_quantity_cast(quantity<Unit, Y>* q) {
    return(&technically_nonportable_quantity_cast<
            typename boost::remove_pointer<T>::type&
           >(*q));
}

//overloads for const quantity

In Christ,
Steven Watanabe