Hello, perhaps i will make a wishlist of topics not dealt in the tutorials. Here is something i miss in each of them: notes at the semantics of data constructors. We read data Pair a b = Pair a b in YetAnotherHaskellTutorial. And that is all ! If we omit "data" here, this would be a silly pleonasm. And no single word about this strange behavior of "data" in every tutorial i read. A similar point: The tutorials teach, that "=" has a similar meaning than "=" in mathematics. But there is a big difference: it is not reflexive. The the right side is the definition of the left. Thus "x=y" has still some kind of temporality, which mathematics doesn't have. Wadler himself describes bunches of lazily computed equations as "dataflows" somewhere. Ok, so much on theory. Here a concrete question: For adapting hws (one of the reasons for me to be here, not many languages have a native web server) to Windows i must work on time. In System.Time i found data ClockTime = TOD Integer Integer 2 questions arise here: Does this define "TOD" (which i do not find elsewhere) together with ClockTime also ? And: Why is this not: data ClockTime Integer Integer = TOD Integer Integer ? Is it just an abbreviation for the first? Or is there a connection to ClockTime as an "abstract data type" (a notion, which would have a subtle different meaning than in OOP - since "instance" is such different thing here). Thanks for your attention, Joost