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Diffstat (limited to 'test/files/pos/viewtest2.scala')
-rwxr-xr-x | test/files/pos/viewtest2.scala | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/test/files/pos/viewtest2.scala b/test/files/pos/viewtest2.scala new file mode 100755 index 0000000000..aa8d33ed6c --- /dev/null +++ b/test/files/pos/viewtest2.scala @@ -0,0 +1,77 @@ +package test; + +object O { + def view (x: String): Ordered[String] = new Ordered[String] { + def compareTo [b >: String <% Ordered[b]](y: b): int = y match { + case y1: String => x compareTo y1; + case _ => -(y compareTo x) + } + } + def view (x: char): Ordered[char] = new Ordered[char] { + def compareTo [b >: char <% Ordered[b]](y: b): int = y match { + case y1: char => x - y1; + case _ => -(y compareTo x) + } + } + def view[a <% Ordered[a]](x: List[a]): Ordered[List[a]] = + new Ordered[List[a]] { + def compareTo [b >: List[a] <% Ordered[b]](y: b): int = y match { + case y1: List[a] => compareLists(x, y1); + case _ => -(y compareTo x) + } + private def compareLists(xs: List[a], ys: List[a]): int = { + if (xs.isEmpty && ys.isEmpty) 0 + else if (xs.isEmpty) -1 + else if (ys.isEmpty) 1 + else { + val s = xs.head compareTo ys.head; + if (s != 0) s + else compareLists(xs.tail, ys.tail) + } + } + } +} + +trait Tree[+a <% Ordered[a]] { + def insert[b >: a <% Ordered[b]](x: b): Tree[b]; + def elements: List[a] +} + +object Empty extends Tree[All] { + def insert[b >: All <% Ordered[b]](x: b): Tree[b] = new Node(x, Empty, Empty); + def elements: List[All] = List(); +} + +class Node[+a <% Ordered[a]](elem: a, l: Tree[a], r: Tree[a]) extends Tree[a] { + def insert[b >: a <% Ordered[b]](x: b): Tree[b] = + if (x == elem) this + else if (x < elem) new Node(elem, l insert x, r) + else new Node(elem, l, r insert x); + def elements: List[a] = + l.elements ::: List(elem) ::: r.elements +} + +object Test { + import O.view; + + private def toCharList(s: String): List[Char] = + if (s.length() == 0) List() + else s.charAt(0) :: toCharList(s.substring(1)); + + def main(args: Array[String]) = { + { + var t: Tree[String] = Empty; + for (val s <- args) { + t = t insert s + } + System.out.println(t.elements) + } + { + var t: Tree[List[char]] = Empty; + for (val s <- args) { + t = t insert toCharList(s) + } + System.out.println(t.elements) + } + } +} |