Hello to everybody I am an new user of Haskel and generally in functional programming and I could say that I am very impressed from this Language. Though I can't understand the use of datatypes. Let's take a firly simple situtation e.g. data Pair a b = Pair a b i.e. an new type with name Pair parameterized over the types a,b with one Constructor named Paid which take two values of type a,b a more complex one would be data Either a b = Left a | Right b i.e a new type named Either parameterized over the types a, b and two Constructors 1. Left which take one value of type a and 2. Right which takes one value of type b I consider that the definitions above are well formulated. Nevertheless I can't understand them quite well. I have read that datatypes are used to define new structures. So, is there any corresponding example in C, sinch I am quite familiar with structures in it? I hope the word C here is allowed here :o) Thanks