Hello, I am a student of computer science at the university of Aachen in Germany and presently do a course about functional programming in haskell. I just wanted to introduce myself, because it is likely to happen that my posting apear frequently in the next couple of month. So my first question is about User-Defined Types. Stating the Gentle Introduction to Haskell 98 (2.2) , i already know that: "Type Constructors and date Constructors are in seperte namespaces. [example]" But according to the chapter (2.2.1) "Recursive Types" i see the polymorphic definition of a tree is: data Tree a = Leaf a | Branch (Tree a) (Tree a) where (Tree a) is obviously the data-constructor out of "the other namespace". I guess that the () is warping Tree a from the "data-constructor-namespace" into the "type-constructor-namespace". Since the gentle-intro implicitly uses (), which i am not used to - i would be happy about some hints about (). That might not be to difficult, i hope. Also i would not regret some hints about "->" which is used in function-type-definitions. I would prefer writing plus :: a,a -> a instead of the ->-variant in order to stress the distinction between arguments and returned type. What is meant that -> is "associating to the right"? Is there a name for '->'? Sincerely Matthias Pfeifer