Carlo Wood wrote:

On Thu, Jun 08, 2006 at 08:59:36PM +0100, Reece Dunn wrote:

...

/** @brief mass */

typedef base_unit< si_tag, mass, prefix::kilo > kilogram;

typedef scaled_unit< kilogram, prefix::kilo > kg; typedef scaled_unit< kilogram, prefix::base > g; typedef scaled_unit< kilogram, prefix::milli > mg;

Surely you mean,

typedef base_unit< si_tag, mass, prefix::base > kilogram;

typedef scaled_unit< kilogram, prefix::base > kg; typedef scaled_unit< kilogram, prefix::milli > g;

No. The reason is that kg is *kilo*gram. So: kg = 1x10^3 g g = 1x10^0 g Also note that Newtons is expressed in terms of kilograms as well, so the type system/internal logic will know that: mass = 1kg speed = 1s distance = 1m results in: force = 1N This was a conscious design on my part: the prefixes should *always* follow the SI unit terminology for SI units. That is why prefix::kilo is specified in the base unit -- so the program knows it needs to convert the unit if using grams. If g were to have prefix::milli, it would have a symbol of mg which makes no rational sense. - Reece _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/