What are type classes in Haskell and how are they used practically?

What are type classes in Haskell and how are they used practically?

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 in Haskell?

Sure! A common example is the Eq type class, which defines the == and /= operators for equality checking. Any type that wants to support equality must implement these functions.

How do I create my own type class?

To create your own type class, you use the class keyword followed by the class name and its methods. For example:

class MyClass a where
    myFunction :: a -> String
``` This defines a type class `MyClass` with a method `myFunction`.

What are some practical uses of type classes?

Type classes are used extensively in Haskell for things like defining common interfaces for data types, implementing generic algorithms, and enabling code reuse across different types.