From 6749e5dd658522cb63600021a9ee5a86f911cfeb Mon Sep 17 00:00:00 2001 From: Martin Odersky Date: Mon, 3 Mar 2003 14:33:53 +0000 Subject: *** empty log message *** --- sources/examples/patterns.scala | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 sources/examples/patterns.scala (limited to 'sources/examples/patterns.scala') 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") + } +} \ No newline at end of file -- cgit v1.2.3