1 files changed, 114 insertions, 0 deletions
diff --git a/docs/examples/fors.scala b/docs/examples/fors.scala
new file mode 100644
index 0000000000..6c969d3519
--- /dev/null
+++ b/docs/examples/fors.scala
@@ -0,0 +1,114 @@
+package examples;
+
+import scala.xml._;
+
+
+object fors {
+
+  val e = Node.NoAttributes ;
+
+  class Person(_name: String, _age: Int) {
+    val name = _name;
+    val age = _age;
+  }
+
+  def printOlderThan20(xs: Seq[Person]): Iterator[String] =
+    printOlderThan20(xs.elements);
+
+  def printOlderThan20(xs: Iterator[Person]): Iterator[String] =
+    for (val p <- xs; p.age > 20) yield p.name;
+
+  val persons = List(
+    new Person("John", 40),
+    new Person("Richard", 68)
+  );
+
+  def divisors(n: Int): List[Int] =
+    for (val i <- List.range(1, n+1); n % i == 0) yield i;
+
+  def isPrime(n: Int) = divisors(n).length == 2;
+
+  def findNums(n: Int): Iterator[Pair[Int, Int]] =
+    for (val i <- Iterator.range(1, n);
+         val j <- Iterator.range(1, i-1);
+         isPrime(i+j)) yield Pair(i, j);
+
+  def sum(xs: List[Double]): Double =
+    xs.foldLeft(0.0) { (x, y) => x + y }
+
+  def scalProd(xs: List[Double], ys: List[Double]) =
+    sum(for(val Pair(x, y) <- xs zip ys) yield x * y);
+
+  type Lst = List[Any];
+
+  val prefix = null;
+  val scope = TopScope;
+
+  val books = List(
+    Elem(prefix, "book", e, scope,
+         Elem(prefix, "title", e, scope,
+              Text("Structure and Interpretation of Computer Programs")),
+         Elem(prefix, "author", e, scope,
+              Text("Abelson, Harald")),
+         Elem(prefix, "author", e, scope,
+              Text("Sussman, Gerald J."))),
+    Elem(prefix, "book", e, scope,
+         Elem(prefix, "title", e, scope,
+              Text("Principles of Compiler Design")),
+         Elem(prefix, "author", e, scope,
+              Text("Aho, Alfred")),
+         Elem(prefix, "author", e, scope,
+              Text("Ullman, Jeffrey"))),
+    Elem(prefix, "book", e, scope,
+         Elem(prefix, "title", e, scope,
+              Text("Programming in Modula-2")),
+	 Elem(prefix, "author", e, scope,
+              Text("Wirth, Niklaus")))
+  );
+
+  def findAuthor(books: Lst) =
+    for (val Elem(_, "book", _, scope, book @ _*) <- books;
+         val Elem(_, "title", _, scope, Text(title)) <- book;
+         (title indexOf "Program") >= 0;
+         val Elem(_, "author", _, scope, Text(author)) <- book) yield author;
+
+  for (val Elem(_, "book", _, scope, b @ _*) <- books;
+       val Elem(_, "author", _, scope, Text(author)) <- b;
+       author startsWith "Ullman";
+       val Elem(_, "title", _, scope, Text(title)) <- b) yield title;
+
+  removeDuplicates(
+    for (val Elem(_, "book", _, scope, b1 @ _* ) <- books;
+         val Elem(_, "book", _, scope, b2 @ _*) <- books;
+	 b1 != b2;
+	 val Elem(_, "author", _, scope, Text(a1)) <- b1;
+	 val Elem(_, "author", _, scope, Text(a2)) <- b2;
+	 a1 == a2) yield Pair(a1, a2));
+
+  def removeDuplicates[a](xs: List[a]): List[a] =
+    if (xs.isEmpty)
+      xs
+    else
+      xs.head :: removeDuplicates(for (val x <- xs.tail; x != xs.head) yield x);
+
+  def main(args: Array[String]) = {
+    Console.print("Persons over 20:");
+    printOlderThan20(persons) foreach { x => Console.print(" " + x) };
+    Console.println;
+
+    Console.println("divisors(34) = " + divisors(34));
+
+    Console.print("findNums(15) =");
+    findNums(15) foreach { x => Console.print(" " + x); };
+    Console.println;
+
+    val xs = List(3.5, 5.0, 4.5);
+    Console.println("average(" + xs + ") = "
+      + sum(xs) / xs.length);
+
+    val ys = List(2.0, 1.0, 3.0);
+    Console.println("scalProd(" + xs + ", " + ys +") = "
+      + scalProd(xs, ys));
+  }
+
+}