What Is Inductive Data Type?

In this example, we define a new type called “List” which can hold elements of any other type “a”. The constructors for this new type are “Nil” and “Cons”.

• Nil: Represents an empty list.
• Cons: Represents a non-empty list and takes two arguments – an element of type “a” and another list of elements of type “a”.

We can now use these constructors to create instances of the List type:

List myList = Cons(1, Cons(2, Cons(3, Nil)))

The above code snippet creates a list of integers with three elements – 1, 2, and 3.

Pattern Matching

Pattern matching allows us to deconstruct values of the new type based on their constructors. It is a powerful tool for manipulating and working with complex data structures.

In our List example, we can use pattern matching to perform operations on the list. Here’s an example:

fun sum(list: List): int {
  match list {
    case Nil => 0
    case Cons(x, xs) => x + sum(xs)
  }
}

The above code snippet defines a function called “sum” that calculates the sum of all elements in a list of integers. The pattern matching allows us to handle both the case of an empty list (Nil) and a non-empty list (Cons).

Conclusion

Inductive data types are a powerful concept in computer programming that allow us to define new types by specifying their constructors. Constructors and pattern matching enable us to create and manipulate complex data structures in a structured and organized manner.

By understanding inductive data types, you can enhance your programming skills and build more efficient and elegant solutions.