Example for beginners to use Arrow composition

typelevel · Oct 7, 2017 · fb60456 · lorenasmith2017 · Oct 10, 2017 · fb60456
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commit fb60456
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diff --git a/core/src/main/scala/cats/arrow/Compose.scala b/core/src/main/scala/cats/arrow/Compose.scala
@@ -8,6 +8,19 @@ import simulacrum.typeclass
  */
 @typeclass trait Compose[F[_, _]] { self =>
 
+  /** 
+    * Here's how you can use `>>>` and `<<<`
+    * Example:
+    * {{{
+    * scala> import cats.implicits._
+    * scala> import cats.arrow._
+    * scala> val f = (_ + 1)
+    * scala> val g = (_ * 100)
+    * scala> (f >>> g)(3)
+    * res0: Int = 400
+    * scala> (f <<< g)(3)
+    * res1: Int = 301
+    * }}}
   @simulacrum.op("<<<", alias = true)
   def compose[A, B, C](f: F[B, C], g: F[A, B]): F[A, C]