Homepage: http://www.cs.utexas.edu/users/novak/units.html
Author: Gordon S. Novak Jr.
License: GPL
From the comments in the code:
; Examples of unit conversion: (glconvertunit from to) ; (glconvertunit 'mile 'foot) ; (glconvertunit 'kilogram 'lb) ; (glconvertunit '(/ (* atto parsec) (* micro fortnight)) '(/ inch second)) ; (glconvertunit '(* acre foot) 'teaspoon) ; (glconvertunit '(/ (* 2000 kilo calorie) day) 'watt) ; average human power ; (glconvertunit '(* 100 kgf 4 m) '(* kilo calorie)) ; calories to climb stairs ; the following require (setq *glunitenable* t) ; (glconvertunit 'kilogram 'lbf) ; mass to weight ; (glconvertunit 'gram 'kilowatt-hour) ; mass to energy ; Examples of unit simplification: ; (glsimplifyunit '(/ meter foot)) ; (glsimplifyunit '(/ joule watt)) ; (glsimplifyunit '(/ joule horsepower)) ; (glsimplifyunit '(/ (* kilogram meter) (* second second))) ; (glsimplifyunit 'atm) ; (glsimplifyunit 'atm 'english) ; (glsimplifyunit '(/ (* amp second) volt)) ; (glsimplifyunit '(/ (* newton meter) (* ampere second))) ; (glsimplifyunit '(/ (* volt volt) (* lbf (/ (* atto parsec) hour))))
Read more at http://www.cs.utexas.edu/users/novak/units.html