Re: Dimensions (was Re: Another Idea for Ada 20XX)

[Wes Groleau <wwgrol@sparc01.ftw.rsc.raytheon.com>]

On another project, I implemented two variations of
dimensioned numbers.  package Units in the deliverable
code was several KSLOC.  It provided a ... is digits ...
for each unit of measure on the project's allowed units list,
all the conversion factors between them, and all the "legal"
operators we could think of.  There were two ways to create
"*" or "/" (1) a generic that would always raise an exception
or a generic that took left, right, and result types and a
multiplier (conversion factor).  It was a pain to write it
and check it, but it worked well as part of a five MegaSLOC
product.

package Unitized_Numbers in the testing software used a
private type with a Units discriminant and a value.
Much smaller, easier to write, but the loss of attributes
and other features of numeric types was a slight disadvantage.
It would have been a much bigger disadvantage if it had to be
used for any complicated algorithms.

-- 
Wes Groleau
http://freepages.rootsweb.com/~wgroleau