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Diffstat (limited to 'tests/untried/pos/viewtest1.scala')
-rw-r--r-- | tests/untried/pos/viewtest1.scala | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/tests/untried/pos/viewtest1.scala b/tests/untried/pos/viewtest1.scala new file mode 100644 index 000000000..38945ad2f --- /dev/null +++ b/tests/untried/pos/viewtest1.scala @@ -0,0 +1,42 @@ +package test + +trait Ordered[a] { + def < (x: a): Boolean +} + +object O { + implicit def view (x: String): Ordered[String] = new Ordered[String] { + def < (y: String) = x.compareTo(y) < 0 + } +} + +object Empty extends Tree[Nothing] +case class Node[c <% Ordered[c]](elem: c, l: Tree[c], r: Tree[c]) extends Tree[c] + +abstract class Tree[+a <% Ordered[a]] { + def insert[b >: a <% Ordered[b]](x: b): Tree[b] = this match { + case Empty => + new Node(x, Empty, Empty) + case Node(elem, l, r) => + if (x == elem) this + else if (x < elem) Node(elem, l insert x, r) + else Node(elem, l, r insert x) + } + def elements: List[a] = this match { + case Empty => List() + case Node(elem, l, r) => + l.elements ::: List(elem) ::: r.elements + } +} + +object Test { + import O.view + + def main(args: Array[String]): Unit = { + var t: Tree[String] = Empty + for (s <- args) { + t = t insert s + } + println(t.elements) + } +} |