Re: [boost] SIunits and quantity library concerns

From: Beman Dawes (bdawes_at_[hidden])
Date: 2001-10-04 14:24:14

At 01:52 PM 10/4/2001, George A. Heintzelman wrote:

 >
 >> |                                But, user defined quantities like
 >> | "apples", "oranges", "fruits", etc are important from the programming
 >> | perspective.
 >>
 >> (5)  This is precisely what I'd like to understand better, and not only
 >> from "the programming perspective"!  I think that "apples" qualifies
 >> neither as a quantity nor as a unit, but I'm willing to be convinced to
 >> the contrary.  For the moment, let me apply the term "qualifier" to
 >> "apples" and such while I struggle to identify some of my concerns.
 >>
 >> (6)  Suppose these qualifiers function as units.  Then it would make
 >> sense to ask what quantities they measure.  I will therefore ask, "What
 >> quantity can I measure in units of apples?"
 >>
 >> (7)  Suppose, instead, these qualifiers function as quantities.  Then
 >> they represent a measurable attribute and so it would make sense to ask
 >> in what units they can be measured.  I will therefore ask, "In what
 >> units can I measure the apple of something?"
 >
 >I think you're missing a couple key words which are obscuring things
 >here. The quantity is apples, the unit is number of apples. Or you
 >might use units of bushels, or crates, or truckloads of apples instead.

That also seems the case to me.  The quantities you can measure in units of 
apples seem to me to be "number of apples", "bushels of apples", etc.  Some 
are convertible to some others, some aren't.

--Beman