Get Programming with Haskell

Lesson 16. Creating types with “and” and “or”

After reading lesson 16, you’ll be able to

• Understand product types in various programming languages
• Use sum types to model problems in new ways
• Think beyond hierarchical program design

In this lesson, you’ll take a closer look at some of the types we’ve already covered. You’ll do this so you can learn more about what makes Haskell’s types unique and how to design programs using types. Most of the types you’ve seen so far are algebraic data types. Algebraic data types are any types that can be made by combining other types. The key to understanding algebraic data types is knowing exactly how to combine other types. Thankfully, there are only two ways. You can combine multiple types with an