On 3/29/07, Matthias Schabel <boost@schabel-family.org> wrote:
While quantity_reinterpret_cast may not be perfectly analogous to reinterpret_cast, it represents the reinterpretation of a raw number as being of a different type, and so I think it's a pretty good name. Just as importantly, I can't think of anything better. Do you have any other ideas? quantity_unsafe_cast? quantity_arbitrary_cast? :)
Sorry, I think I muddied the waters here - I agree that quantity_reinterpret_cast should be reserved for those cases where access to the raw data is necessary. I was just saying that we can write things like
quantity<SI::length,double> q; quantity<SI::length,int> r; quantity<CGS::length,double> s; quantity<CGS::length,int> t;
q = quantity<SI::length,double>(r); q = quantity<SI::length,double>(s); q = quantity<SI::length,double>(t);
already, so the only non-degenerate use case of quantity_cast is to take a raw value and return a quantity:
q = quantity_cast< quantity<SI::length,double> >(1.5);
Maybe I'm missing something here, but why shouldn't this last cast be done using a constructor instead: q = quantity<SI::length,double>(1.5*meter); This way, the set of library capabilities is no different, but the resulting code is more explicit, and quantity_cast cannot be used in a type-unsafe way. Further, it's name suggests that quantity_cast only casts between quantities, not between underlying values and quantites. Taking a raw value and constructing a quantity from it should be the sole purview of the quantity constructor. Zach Laine