From c5c9c4f1432391f6af9202dd89872e5aae92ca58 Mon Sep 17 00:00:00 2001
From: Jon Pretty <jon.pretty@propensive.com>
Date: Thu, 9 Nov 2017 09:20:20 +0000
Subject: Added Scaladocs

---
 examples/src/main/scala/show.scala | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'examples/src/main/scala/show.scala')

diff --git a/examples/src/main/scala/show.scala b/examples/src/main/scala/show.scala
index 4594bff..9da507c 100644
--- a/examples/src/main/scala/show.scala
+++ b/examples/src/main/scala/show.scala
@@ -6,21 +6,39 @@ import scala.language.higherKinds
 import magnolia._
 import scala.language.experimental.macros
 
+/** shows one type as another, often as a string
+ *
+ *  Note that this is a more general form of `Show` than is usual, as it permits the return type to
+ *  be something other than [[String]]. */
 trait Show[Out, T] { def show(value: T): Out }
 
+/** companion object to [[Show]] */
 object Show {
+
+  /** the type constructor for new [[Show]] instances
+   *
+   *  The first parameter is fixed as [[String]], and the second parameter varies generically. */
   type Typeclass[T] = Show[String, T]
+
+  /** creates a new [[Show]] instance by labelling and joining (with `mkString`) the result of
+   *  showing each parameter, and prefixing it with the class name */
   def combine[T](ctx: CaseClass[Typeclass, T]): Show[String, T] = new Show[String, T] {
     def show(value: T) = ctx.parameters.map { param =>
       s"${param.label}=${param.typeclass.show(param.dereference(value))}"
     }.mkString(s"${ctx.typeName.split("\\.").last}(", ",", ")")
   }
 
+  /** choose which typeclass to use based on the subtype of the sealed trait */
   def dispatch[T](ctx: SealedTrait[Typeclass, T]): Show[String, T] = new Show[String, T] {
     def show(value: T): String = ctx.dispatch(value) { sub => sub.typeclass.show(sub.cast(value)) }
   }
 
+  /** show typeclass for strings */
   implicit val string: Show[String, String] = new Show[String, String] { def show(s: String): String = s }
+  
+  /** show typeclass for integers */
   implicit val int: Show[String, Int] = new Show[String, Int] { def show(s: Int): String = s.toString }
+  
+  /** bind the Magnolia macro to this derivation object */
   implicit def gen[T]: Show[String, T] = macro Magnolia.gen[T]
 }
-- 
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