On 18/03/2012 21:45, Grahame Grieve wrote: > ok, so you say it should be computable, but then allow a fixed unit of one, > and some other code as well. And this in a subclass of Quantity, so you > could always use it or encounter it in place of quantity. So if that's the > case, why not simply make it a property of Quantity?
because it only applies in a small number of cases. Most Quantity instances will never have this because they don't represent this kind of information. - thomas
