Laurent writes: > Examples and details here: > https://github.com/Metaxal/measures
At first glance, I miss the notion of "dimension", which defines if two units are compatible, i.e. can be converted. If I understand your approach correctly (which I am not sure about), you consider each product of unit symbols as distinct. That means if someone enters a pressure in Pascal, and multiplies by an area in square meters, the result cannot be added to a force in Newton, although a Pascal is by definition a Newton per square meter. BTW, I can offer my Clojure units library for inspiration, if someone wants to implement a straightforward approach based on run-time checks: http://code.google.com/p/clj-units/ It deals with dimension compatibility, and allows the definition of any number of unit systems. Like pretty much any library I know of, it doesn't handle the particularity of the SI system of having distinct incompatible units with equal dimension, such as Bq (Bequerel) and Hz (Hertz), which are both 1/s but reserved for specific applications. My library will let you convert Hz to Bq without complaint. Konrad. ____________________ Racket Users list: http://lists.racket-lang.org/users
