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1 files changed, 28 insertions, 0 deletions

diff --git a/sources/examples/patterns.scala b/sources/examples/patterns.scala
new file mode 100644
index 0000000000..3e4d5a5826
--- /dev/null
+++ b/sources/examples/patterns.scala
@@ -0,0 +1,28 @@
+module patterns {
+
+  trait Tree {}
+  case class Branch(left: Tree, right: Tree) extends Tree {}
+  case class Leaf(x: Int) extends Tree {}
+
+  val tree1 = Branch(Branch(Leaf(1), Leaf(2)), Branch(Leaf(3), Leaf(4)));
+
+  def sumLeaves(t: Tree): Int = t match {
+    case Branch(l, r) => sumLeaves(l) + sumLeaves(r)
+    case Leaf(x) => x
+  }
+
+  def find[a,b](it: Iterator[Pair[a, b]], x: a): Option[b] = {
+    var result: Option[b] = None();
+    while (it.hasNext && result.isNone) {
+      val Pair(x1, y) = it.next;
+      if (x == x1) result = Some(y)
+    }
+    result
+  }
+
+  def printFinds[a](xs: List[Pair[a, String]], x: a) =
+    find(xs.elements, x) match {
+      case Some(y) => System.out.println(y)
+      case None() => System.out.println("no match")
+    }
+}
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