Lots of great Haskell material on his site. In particular this derivation of the State monad from first principles was the "Aha!" moment for me understanding mo

Lots of great Haskell material on his site. In particular this derivation of the State monad from first principles was the "Aha!" moment for me understanding monads. http://dev.stephendiehl.com/begin/index.html#monads http://dev.stephendiehl.com/begin/index.html#monads