[Axiom-developer] Unit package question

[C Y]

Hi all.  I have a rather odd question, and I don't know if this is
something Axiom even will permit, but it would be useful to know, so...

I want to be able to teach Axiom how to use units.  There are a number
of surprisingly annoying features to handle based on my experience with
Maxima, and one of the worst is the following:

If I enter an expression, Axiom automatically formats it and orders it
according to internal rules.  See
http://www.axiom-developer.org/zope/mathaction/address@hidden
for an example of this.  Normally, this is what one wants to do.  What
I'm not sure of is how to instruct Axiom to display things that are
Units at the end of an expression, e.g.

        kg*m
a*b*z  ------
          2
         s

In Maxima it requires some rather alarming hackery with the display
code to avoid the same default behavior Maxima exhibits.  In one sense
Axiom is an ideal place for certain types of unit operations, since I
can presumably do things like assign both inches and meters the type
Length, and assign simplification rules accordingly :-). but I don't
know how to impliment the display logic above.  Based on the Maxima
experience, I'm guessing the infastructure might not be in place to
support something like this, given it is rather non-standard in normal
mathematical environments.  Is there anybody who knows what the correct
approach to this would be?

Cheers,
CY

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