API improvements and better examples

1 files changed, 24 insertions, 0 deletions

diff --git a/examples/src/main/scala/default.scala b/examples/src/main/scala/default.scala
new file mode 100644
index 0000000..1f602f9
--- /dev/null
+++ b/examples/src/main/scala/default.scala
@@ -0,0 +1,24 @@
+package magnolia.examples
+
+import scala.language.existentials
+import scala.language.higherKinds
+
+import magnolia._
+import scala.language.experimental.macros
+
+trait Default[T] { def default: T }
+
+object Default {
+  type Typeclass[T] = Default[T]
+  def join[T](ctx: JoinContext[Default, T]): Default[T] = new Default[T] {
+    def default = ctx.construct { param => param.typeclass.default }
+  }
+
+  def dispatch[T](ctx: DispatchContext[Default, T])(): Default[T] = new Default[T] {
+    def default: T = ctx.subtypes.head.typeclass.default
+  }
+
+  implicit val string: Default[String] = new Default[String] { def default = "" }
+  implicit val int: Default[Int] = new Default[Int] { def default = 0 }
+  implicit def generic[T]: Default[T] = macro Magnolia.generic[T]
+}