Am 15.04.2014 21:29, schrieb John David Reaver:
Hello! I am happy to publicly announce the quantities package:
Hackage: http://hackage.haskell.org/package/quantities Github: https://github.com/jdreaver/quantities
I feel this package is complete enough as of version 0.3.0 (released today) to announce it to the public.
I have programmed something similar years ago, first for Haskell 98 numeric classes and then for numeric-prelude. My implementation does not use an expression tree for the physical dimensions. Instead it uses a vector of base dimensions and constructs reasonable units only for string output. http://hackage.haskell.org/package/numeric-prelude-0.4.1/docs/Number-SI.html You can play around with it by unpacking the numeric-prelude package and run 'make ghci' thielema@sputnik:/tmp> cabal unpack numeric-prelude Unpacking to numeric-prelude-0.4.1/ thielema@sputnik:/tmp> cd numeric-prelude-0.4.1/ thielema@sputnik:/tmp/numeric-prelude-0.4.1> make ghci ... *Main> 25*meter/second :: SIDouble ... 25.0 m/s *Main> minute/second :: SIDouble 60.0 *Main> ampere*volt :: SIDouble 1.0 W There are many more libraries for handling of physical dimensions: http://www.haskell.org/haskellwiki/Physical_units You may add 'quantities' there.