Functions, functions, functions; Haskell is all about functions. When writing Haskell code we create, compose and apply functions to achieve our goal. What is a function In Haskell a function takes one or more things (referred to as arguments), and will give you back something else (referred to as the output or return value). So to recap, a Haskell function takes something and gives something else back. This is all a ‘normal’ function can do in Haskell, I will discuss the ‘non-normal’ functions, ones that can effect the program state later, they are more advanced.

Welcome back to the next post now we will be learning about List and comprehensions, they form a large part of a typical Haskell program, so lets find out more about them now. The List 1 2 3 4 5 6 7 8 9 10 11 12 13 14 nums :: [Int] nums = [1,2,3] chars :: [Char] chars = ['h', 'a', 's', 'k', 'e', 'l', 'l'] str :: String str = "haskell" funcs :: [[Int] -> Int] funcs = [product, sum] evenList :: [Int] evenList = [0,2.

Our research into Haskell Lists continues. Before we can look into using recursive functions with lists, I think first we need to cover what recursion is. In my opinion recursion is one of the most important concepts for any Functional Programmer. Recursion: Where a function calls its self from within its definition. Case: A condition that could happen, eg the number could be zero or it may not be.