In reference to Alan K's comment and Augustin Mrazik's response about
"units," you might want to take a look at Siren's music magnitude classes
(e.g., pitch, duration, loudness with units such as Hz, Sec or dB). There are a
few interesting design patterns in there about interoperating with numbers and
other magnitudes, mixed-mode arithmetic within a "species" (e.g., 1/4 beat + 30
msec), and the separation of representation (what do I represent? (I call this
species)) from implementation (what "units" do I use? (I use classes for this)).

There are many kinds of units in the world, but a smaller number of
fundamental dimensions, and any model should take into account that the
different measures, e.g., of distance or temperature, share some behaviors but
also have some subtly different semantics (e.g., linear vs. angular distance).

stp

_ Stephen Travis Pope
_ Center for Research in Electronic Art Technology (CREATE)
_ Dept. of Music, Univ. of California, Santa Barbara (UCSB)
_ stp at create.ucsb.edu,  http://www.create.ucsb.edu/~stp/