GIGO: words unreadable aloud

Chapter 3, Exercise 5, Thinking in Scala

For this exercise, the wrinkle is that Scala's "for" has no break statement. We simulate it here, with an exception. The bodies of ifs and whiles are already anonymous nested functions anyway; and that is the kind of thing we are passing as the second ("body") argument to the tfor function.

case class breakEx extends Throwable; 
object c3x5 {
    def break = { throw new breakEx(); } 
    def tfor (iter: Iterator[Int]) (def body: Int => unit): unit = {
        try {
            while( iter.hasNext ) {
                body(iter.next);
            }
        }
        catch { case breakEx => }
    } 
    def main ( args: Array[String] ) = {
        tfor (Iterator.range(1,101) ) { i =>
            if (i == 47) { break; }
            Console.println( i.toString() );
        }
    }
}

This will not satisfy situations where one wants to use the final value of the iterator variable, after the loop completes. A strategy similar to the following should suffice for those cases:

case class breakEx extends Throwable; 
object c3x5n {
    def break = { throw new breakEx(); } 
    def tfor (iter: Iterator[Int]) (def body: Int => unit): unit = {
        try {
            while( iter.hasNext ) {
                body(iter.next);
            }
        }
        catch { case breakEx => }
    } 
    def main ( args: Array[String] ) = {
        var j : Int = _;
        tfor (Iterator.range(1,101) ) { i =>
            if (i == 47) { break; }
            Console.println( i.toString() );
            j = i;
        }
        Console.println( "After the tfor, j is " + j.toString() );
    }
}

5:23:43 PM comment/