"Jonathan Turkanis" <technews@kangaroologic.com> wrote
Andy Little wrote:
BTW why doesnt boost::rational have a 'value_type' member rather than the obscure 'int_type'?
You'd have to ask Paul. I would guess it's mean to reflect the requirements on the template parameter.
If you are using a rational , you are kind of going to figure out that the value_type should be an integer... I hope. OTOH this requirement can be imposed. However rational should be seen as one of a family of UDT value_type-operable types. (std::complex , boost::rational and boost::interval can all be Op'ed with their value_type. And in fact have a remarkably similar set of function signatures) The nearest precedent in the standard is complex which does have a 'value_type' member. In using UDTs that implement numeric types it is reasonably common to want to know the 'value_type', for which purpose I use a to_value_type<T> function, which by default recursively inspects T::value_type for non-inbuilt types. In determining rational (and incidentally interval) value_types I have had to create specialisations which is tedious. There seems to be no particular reason not to follow the standard name for the value_type in either rational or interval. regards Andy Little