-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Steven Watanabe Sent: Wednesday, March 28, 2007 12:03 PM To: boost@lists.boost.org Subject: Re: [boost][Review] Quantitative Units library review begins today March 26
AMDG
Eric Lemings <lemings <at> roguewave.com> writes:
Allowing conversion between units having different dimensions and allowing fundamental units whose dimensions are not fundamental e.g. quarts for volume is very very difficult to implement. Off hand, I think that it requires defining some special system (probably SI) and converting through that system.
It's not that difficult
How would you do it? Using some special set of units has problems with extensibility. Suppose someone tried to add currency and used US dollars as the base and at the same time someone else used euros as the base.
Ah sorry. I misread your initial comment. I thought you were referring to units with multiple but same dimensions rather than units with different dimensions. In such cases, it's not just very difficult but is completely impossible according to the rules for dimensional analysis. Eric.