A type class represents a group of types that share a common behavior. A type class is to a type what a class is to an object. As with traditional classes, a type class can define methods. These methods can be invoked on all types that belong to the type class.
Type classes were introduced in the Haskell programming language. However, thanks to the power of implicits, we can also use them in Scala. In Scala, type classes are not built-in language constructs (like they are in Haskell) and, as a result, we need to write a bit of boilerplate code to define them.
In Scala, we declare a type class by using trait, which accepts a type parameter. For instance, let's define a Combine type class that allows for combining two objects into one, as follows:
trait Combine[A] {
def combine(x: A, y: A): A
}Then, we can define two type class instances for Combine, as follows:
- One for
Int, which will add the two arguments - One for
String, which will concatenate them
The code definition...