Type Classes

2016-06-21

Most languages support polymorphism of one sort or another. In the type classes video we will discuss some of the different approaches you will see in different languages, and then introduce Haskell’s method. Then we will go over the functor type class, which allows you to define the higher order function map for any type you want.

Videos

• Type Classes
• Functors and Applicatives

In-class code

• Haskell code
• Shell session

Further Reading

There is a lot of theory behind type classes. Here are some interesting readings if you would like to learn more.

• Typeclassopdeia Read this if you want a deeper understanding of type classes.
• Typeclassopdeia (Slide Show version)
• Variadic functions in Haskell They used type classes to trick Haskell into allowing us to have functions with a variable number of parameters!