[Org-jutil-devel] quantities and units

[Marko v. D. <Mar...@cs...>]

I've been working on a system of quantities and units. Initially I implemented 
each unit and quantity in a separate class, but now I'm implementing derived 
quantities, the amount of classes is exploding. I want to implement at least 
all quantities and units on http://physics.nist.gov/cuu/Units/units.html.

All classes are singletons, but even if they are not implemented that way, the 
implementation will always try to use the same objects instead of creating 
new ones. I was planning to create a class SI (or something like that) anyway 
for convenience (not having to import zillions of classes), so I'm wondering 
if instead of only providing final static constants in that class, I should 
also put the instantiation of different units in there, and get rid of the 
subclasses. That would mean that base quantities (and units) would have to be 
singletons in order to work since the only useful test would be == when they 
are all instances of the same class (not that I have any problem with that 
since there is no use for more than 1 instance of a certain base quantity).

I can't really find a good reason now for creating a separate class for every 
different quantity/unit. It seemed like a good idea at first, but now ...

In other words, I want your $0.02


Marko
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