Announcing deka, a library for decimal arithmetic. Why decimal arithmetic is important is discussed at length at http://speleotrove.com/decimal/ but for a short explanation, go into ghci and type: print $ 0.1 + 0.1 + 0.1 This is 0.3, right? But on my machine I get 0.3 plus a small fraction, which is simply not acceptable for applications where it is essential to get exact results, such as financial applications. deka is a binding to the decNumber C library, a thoroughly tested and fast implementation of decimal arithmetic. deka is fully tested and I encourage you to run the tests using the usual "cabal test" method. deka is available at http://hackage.haskell.org/package/deka and is on Github at https://github.com/massysett/deka Because deka is a binding to the decNumber C library, first you will need to install decNumber. An easy to install version with the GNU autotools is at: https://github.com/massysett/decnumber/releases decNumber's website is at http://speleotrove.com/decimal/decnumber.html A literate Haskell file illustrating the use of deka is available at https://github.com/massysett/deka/blob/master/lib/Data/Deka/Docs/Examples.lh...