Re: [boost] Quantity library: any interest?

From: Robert Ramey (ramey_at_[hidden])
Date: 2003-04-27 15:13:48

From: =?iso-8859-1?Q?Terje_Sletteb=F8?= <tslettebo_at_[hidden]>

One more uninformed opinion?  It would seem to me the angle
isn' dimensionless.  and it has units of measure of degrees/radians or?
What am I missing here?

Money.
There is a "dimension" value which is subject to units of measure
dollars, francs, etc.  The difference between this dimension and the
rest we've talked about is that the conversion of unitis of measure
change dynamically in a world of fluctuating exchange rates.

Position.
Screen Position in pixels X Transform(Screen Attributes, Real World Attribute)
        = Real World Position

Screen Position and RealWorldPosition are related dimensionally
though they don't have the same units of measure as this is related their
coordinate system. So it doesn't make any sense to compose them aritmetically
without a transform. It may be possible to generate the tranform automagically
for any pair of dimensionally related quantiies if a canonical
transform is supplied for each unit of measure/Coordinate system.

Some time ago I made a quantity library along with an article
that never got published.  It doesn't use templates all that much
and its not suitable as basis for a boost library, but it might contain
an idea or two that might be useful to included in the new system.
If there's interest, I can upload it to the files section.

Robert Ramey