I'm at a crossroads in my Haskell study

Chapter 7 in SJT is "Defining functions over lists" --- this is arguably the meat-and-potatoes chapter of the entire book, and it has some great exercises.

However, I was a bit concerned with the given implementation of split because it went over the same part of the list twice:

split :: String -> [Word]
split [] = []
split st
  = (getWord st) : split (dropSpace (dropWord st))

It looks interesting. So I'm pondering whether to study the entire prelude or continue on with the text.

I think the book is better for me, so that I can learn more of the Haskell system - modules, type classes, infinite lists, monads, algorithm analysis.

It will make me a complete programmer, ready for other interesting articles and exercises and contributions to the Haskell community.