Re: SIunits and quantity library concerns

From: Eric Ford (eford_at_[hidden])
Date: 2001-10-05 16:53:12

> I disagree. If we develop tags, then I think these things have an SI 
> unit of Amount<>, which can be measured in units of moles, or 
> individual items. Anything can be measured in this units, not just
the 
> atoms and molecules of chemistry.

I'm not sure I like the idea of a count being given a dimension, but I
now think my concerns don't matter.  Since SI defines ammount to be a
"dimension", we better treat it as such regardless of whether we agree
or disagree.  The library won't gain wide acceptance if it can't
support SI.  (Besides the people who worked that out probably thought
about it more than most of us.)  So I now feel we should include
Amount(OfSubstance) as a dimension in a unit library.

So I propose we deal with things like cartons_of_apples and a unit
with dimension Ammount, units cartons, and tag apples. 
cartons_of_granny_smith_apples would get a second tag to identify them
as granny_smith.  

My initial guess is that multiple tags should generally be handeled by
taging a prevously taged unit.  Can someone identify a problem with
requiring multiple tags to be heirarchical? 

E