On 13 April 2011 21:26, Tim Chevalier <catamorphism at gmail.com> wrote: > IO doesn't obey the monad laws, due to the presence of seq in Haskell. > Sad but true... See also a previous discussion about IO and the Monad laws: http://www.haskell.org/pipermail/haskell-cafe/2010-March/074001.html