smarter · November 18, 2019 08:55 · kwark · Nov 15, 2019 · smarter · Nov 18, 2019
diff --git a/fmap.scala b/fmap.scala
 // Compiles with https://github.com/lampepfl/dotty/pull/4672
 // ./bin/dotc -classpath "$(coursier fetch -p org.typelevel:cats-core_2.13:2.0.0)" out/fmap.scala
 import cats._
 import cats.implicits._

 object Test {
  val fmap: [A, B] -> (A => B) => [F[_]] -> F[A] => (given Functor[F]) => F[B] = [A, B] -> (f: A => B) => ([F[_]] -> (fa: F[A]) =>  (given ev: Functor[F]) => fa.map(f))

  val addOne = fmap((x: Int) => x + 1)

  val x = addOne(Option(42))
  val y = addOne(List(1,2,3))
 }
	// Compiles with https://github.com/lampepfl/dotty/pull/4672
	// ./bin/dotc -classpath "$(coursier fetch -p org.typelevel:cats-core_2.13:2.0.0)" out/fmap.scala
	import cats._
	import cats.implicits._

	object Test {
	val fmap: [A, B] -> (A => B) => [F[_]] -> F[A] => (given Functor[F]) => F[B] = [A, B] -> (f: A => B) => ([F[_]] -> (fa: F[A]) => (given ev: Functor[F]) => fa.map(f))

	val addOne = fmap((x: Int) => x + 1)

	val x = addOne(Option(42))
	val y = addOne(List(1,2,3))
	}