Scala Programming Projects

Usage examples

Whenever you have a function A => B, you can lift it to make a function F[A] => F[B], as long as you have a Functor[F] instance in scope, as follows:

def square(x: Double): Double = x * x
def squareVector: Vector[Double] => Vector[Double] =
  Functor[Vector].lift(square)
  squareVector(Vector(1, 2, 3))
// res0: Vector[Double] = Vector(1.0, 4.0, 9.0)
def squareOption: Option[Double] => Option[Double] =
  Functor[Option].lift(square)
  squareOption(Some(3))
// res1: Option[Double] = Some(9.0)

Another handy function is fproduct, which tuples value with the result of applying a function:

Vector("Functors", "are", "great").fproduct(_.length).toMap //res2: Map[String,Int] = Map(Functors -> 8, are -> 3, great -> 5)

We created Vector[(String, ...