Hi all, One of the ideas I had while reading the book but didn't have the guts to pull off without asking for feedback was splitting the More on Datatypes module in Intermediate Haskell. As of now, it has a first part which describes an assortment of important datatype techniques (enumerations, records and a more formal presentation of parametrized types - using Maybe as example) and then moves on to a long discussion of binary trees and how to define maps and folds for arbitrary data structures. The coupling of these two parts is very loose (the only concept of the first part needed for the data structure discussions is parametrization) and probably does not justify them being glued together to make such a long (27k) module. Another related issue is that one important omission from the Beginner's Track is an explanation of newtype, and I guess More on Datatypes would be the right place to put it. That would make the module even longer, however, and would be another reason to make the split. The only thing I am not sure of is a good name for the second "half" of More on Datatypes in case of a split. The obvious choice would be "Trees and ???" (I have no idea of a good concise term to replace the ???), although maybe something more generic like "Introduction to Data Structures" could work. Thanks, and see you, Daniel Mlot P.S.: By the way, Apfelmus has moved Type Declarations to just before Pattern Matching. Probably the right thing to do (it just didn't fit very well in Haskell Basics), but it will also require some reworking of Type Declarations (when I made that module more verbose I envisioned it as a preparation for a more general Pattern Matching discussion several modules ahead, but with the rearranging the redundancies are probably too obvious). I will give it a try soon.