How do I implement type classes in Haskell?

How do I implement type classes in Haskell?

To implement a type class in Haskell, you start by defining the class with its methods. For example:

class Show a where
    show :: a -> String

Can you give me an example of a type class implementation?

Sure! Here's an example of implementing the Show type class for a custom data type:

data Person = Person String Int

instance Show Person where
    show (Person name age) = name ++ " is " ++ show age ++ " years old."

What if I want to create a type class with multiple methods?

You can define multiple methods in a type class like this:

class Shape a where
    area :: a -> Float
    perimeter :: a -> Float