bistaumanga · July 30, 2016 15:28 · Jul 30, 2016
diff --git a/Monoid.scala b/Monoid.scala
@@ -0,0 +1,37 @@
+import simulacrum.{op, typeclass}
+
+import scala.language.experimental.macros
+
+object MyOps extends machinist.Ops{
+  override def operatorNames: Map[String, String] = Map(
+    "$bar$plus$bar" -> "plus"
+  )
+}
+
+case class MyInt(i: Int) extends AnyVal
+
+@typeclass trait Monoid[@specialized(Int, Double) T]{
+  def zero: T
+  @op("|+|") def plus(lhs: T, rhs: T): T
+}
+
+object Monoid{
+  trait Ops[A] {
+    def |+|(rhs: A): A = macro MyOps.binop[A, A]
+  }
+}
+
+object MinMonoidMyInt extends Monoid[MyInt]{
+  override def zero: MyInt = MyInt(Int.MaxValue)
+  override def plus(a: MyInt, b: MyInt): MyInt = MyInt(a.i min b.i)
+}
+
+object MinMonoidInt extends Monoid[Int]{
+  override def zero: Int = Int.MaxValue
+  override def plus(lhs: Int, rhs: Int): Int = lhs min rhs
+}
+object Test extends App{
+  import Monoid.ops._
+  implicit val monoid = MinMonoidMyInt
+  println(MyInt(4) |+| MyInt(7) )
+}