What are type classes in Haskell and how do I use them?

What are type classes in Haskell and how do I use them?

Type classes in Haskell are a way to define a set of functions that can operate on different types. They allow for polymorphism, meaning you can write generic code that works with any type that implements the type class.

Can you give me an example of a type class?

Sure! A common example is the Eq type class, which defines equality. Any type that implements Eq must provide an implementation for the == and /= operators.

How do I create my own type class?

To create your own type class, use the class keyword followed by the class name and the type variables. For example: class MyClass a where ....

What about instances? How do I define them?

You define an instance of a type class for a specific type using the instance keyword. For example: instance MyClass MyType where ....

Are there any built-in type classes I should know about?

Yes, some important built-in type classes include Show, Read, Ord, and Num. Each serves a different purpose in Haskell.