Michael Snoyman wrote: > > newtype MilesPerGallon = MilesPerGallon Double deriving Show > newtype Gallon = Gallon Double deriving Show > newtype Mile = Mile Double deriving Show > You may want to have a look at Björn Buckwalter's dimensional library http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dimensional Regards, apfelmus