Option type

Option is one of the type constructors that Scala provides. The question arises, what's a type constructor? The answer is simple; it lets you construct a type. We'll take two statements:

1. Option is a type constructor
2. Option[Int] is a type

Let's discuss these in detail. When I say Foo is a type constructor, it means that Foo expects you to provide a particular type in the form of a parameter. It looks like Foo[T], where T is an actual type. We call them type parameters and we'll talk about them in the following few sections.

In the second statement, we saw that we gave an Int type to our Option type constructor in brackets and it formed a type. If you try this in the Scala REPL, it'll tell you exactly the same thing we discussed:

scala> val a: Option = Some(1) 
<console>:11: error: class Option takes type parameters 
       val a: Option = Some(1) 
 
scala> val a: Option[Int] = Some(1) 
a: Option[Int] = Some(1) 

In simple words, the Option[T] type represents an optional value...