## Conversion of Units of Measurement

This is a demonstration of a program that converts between different units
of measurement, or combinations of units. It can also simplify
expressions of units.
A units expression is a unit name, such as `meter`

,
a number such as `2.5`

, a product of two or more unit expressions
`(* expr1 ... exprn)`

,
or a quotient of two unit expressions `(/ expr1 expr2)`

.
Common abbreviations such as `ft`

are allowed.

An example is `(/ (* atto parsec) (* micro fortnight))`

.

When the program is started, a window is created containing a command menu
and input and output areas. Click the appropriate menu items to run
the demo.

## Instructions