On Thu, Mar 3, 2011 at 2:38 PM, Matthias Schabel <boost@schabel-family.org> wrote:

Maybe http://www.boost.org/doc/libs/1_46_0/doc/html/boost_units/Quantities.html#boost_units.Quantities.Quantity_Construction_and_Conversion?

"implicit conversion between quantity<Unit1,Y> and quantity<Unit2,Z> is allowed if Unit1 reduces to exactly the same combination of base units as Unit2 and if Y and Z are convertible."

Doesn't si::length reduce to the base unit "si::meter_base_unit:unit_type"? If it doesn't what is the base unit of si::length?

quantity<si::length> is shorthand for quantity<si::length,double>. si::length is type representing a length in the SI system, so it encapsulates both the dimensionality of length and the specific measure of length.

I understand that si::length is a dimension. A value in a dimension has to have a particular unit of measurement. In the case of length a value can be either meters, kilometers, nanometers, centimeters, etc. The chosen unit of measurement for si::length is meters.

Shouldn't I be able to create quantity of the si systems length (which is in meters) and a quantity of type meters and have them work together?

Ryan