Get Programming with Haskell

Lesson 13. Type classes

After reading lesson 13, you’ll be able to

• Understand the basics of type classes
• Read type class definitions
• Use common type classes: Num, Show, Eq, Ord, and Bounded

In this lesson, you’re going to look an important abstraction in Haskell’s type system: type classes. Type classes allow you to group types based on shared behavior. At first glance, type classes are similar to interfaces in most object-oriented programming languages. A type class states which functions a type must support in the same way that an interface specifies which methods a class must support. But type classes play a much more important role in Haskell than interfaces do in languages such as Java and C#. The major difference is that as you dive ...