More tests and other odds and end

 - Add tests that work to pos/neg, tests that don't work yet to pending/pos/neg.
 - Also, change .gitignore to allow for a local directory.
 - Also add a draft page to the docs.

1 files changed, 61 insertions, 0 deletions

diff --git a/tests/pos/Monoid.scala b/tests/pos/Monoid.scala
new file mode 100644
index 000000000..f6004cdf3
--- /dev/null
+++ b/tests/pos/Monoid.scala
@@ -0,0 +1,61 @@
+package strawman.typeclasses
+
+trait SemiGroup[T] {
+  def append(x: T, y: T): T
+}
+object SemiGroup {
+  class Ops {
+    implicit class InfixAppend[T: SemiGroup](self: T) {
+      def |+| (other: T): T = implicitly[SemiGroup[T]].append(self, other)
+    }
+  }
+  object ops extends Ops
+}
+
+trait Monoid[T] extends SemiGroup[T] {
+  val id: T
+}
+object Monoid {
+  object ops extends SemiGroup.Ops
+}
+
+trait Ring[T] extends Monoid[T] {
+  val zero = id
+  val one: T
+  def product(x: T, y: T): T
+}
+object Ring {
+  class Ops extends SemiGroup.Ops {
+    implicit class InfixProduct[T: Ring](self: T) {
+      def |*| (other: T): T = implicitly[Ring[T]].product(self, other)
+    }
+  }
+  object ops extends Ops
+}
+
+
+
+object Test {
+  implicit object StringMonoid extends Monoid[String] {
+    def append(x: String, y: String): String = x ++ y
+    val id = ""
+  }
+
+  implicit object IntRing extends Ring[Int] {
+    def append(x: Int, y: Int) = x + y
+    val id = 0
+    val one = 1
+    def product(x: Int, y: Int) = x * y
+  }
+
+  import Monoid.ops._ // works in dotty, fails in scalac
+  import Ring.ops._
+  "abc" |+| "def"
+  "abc" |+| StringMonoid.id
+  StringMonoid.id |+| "abc"
+
+  1 |+| 2
+  3 |*| 3
+
+
+}