How does `.get("key")` on a `Option[Map[String,String]]` work

Question

When I create an Option[Map[String,String]] like this

scala> val x = Some(Map("foo" -> "bar"))
x: Some[scala.collection.immutable.Map[String,String]] = Some(Map(foo -> bar))

Why does this call work:

scala> x.get("foo")
res0: String = bar

Since x is of instance Option and there is no method get that accepts parameters on the case class Some and that class is final, this should not work. The IDE is not giving any hints, why this works.

Answer 1

Option has a get method that has no parameter list. You call it by just using the name get without an argument list:

scala> val x = Some(Map("foo" -> "bar"))
x: Some[scala.collection.immutable.Map[String,String]] = Some(Map(foo -> bar))

scala> x.get  // Note: no arguments
res0: scala.collection.immutable.Map[String,String] = Map(foo -> bar)

What you get back is, obviously, the Map.

The ("foo") after get is applied to the Map. Note that this is shortcut syntax for calling the apply method on the Map. So, x.get("foo") is equivalent to x.get.apply("foo").

scala> x.get("foo")  // Shortcut syntax
res2: String = bar

scala> x.get.apply("foo")  // For this
res3: String = bar