[Scala] A little code

[wtd]

code:

// A MyRange object could really just be an Iterator[Int]. class MyRange(val start: Int, val end: Int) extends Iterator[Int] {    protected var current = start    def hasNext = current <= end    def next = {       val c = current       current += 1       c         } } // And a MyExclusiveEndedRange. class MyExclusiveEndedRange(override val start: Int, override val end: Int)  extends MyRange(start, end) {    override def hasNext = current < end }

[wtd]

code:

// Let's number the numbers in a range. var count = 0 val r = new MyRange(5, 10) while (i.hasNext) {    Console.println(count + ": " + i.next)    count += 1 } // Easier? var count = 0 val r = new MyRange(5, 10) for (val x <- r) {    Console.println(count + ": " + x)    count += 1 } // Not easy enough. val r = new MyRange(5, 10) val i = r.counted for (val x <- i)    Console.println(i.count + ": " + x) // How about a new class? class EnumeratedIterator[+T](val targetIterator: Iterator[T])  extends Iterator[(Int, T)] {    protected val iter = targetIterator.counted    def hasNext = iter.hasNext    def next = {       val n = iter.next       (iter.count, n)    } } // And now... val r = new MyRange(5, 10) for (val (count, x) <- new EnumeratedIterator(r))    Console.println(count + ": " + x)

[wtd]

code:

// Use the power of the standard library! for (val (x, count) <- new MyRange(5, 10) zipWithIndex)    Console.println(count + ": " + x) // Let's try some XML. val xml = <list>    { for (val (x, c) <- new MyRange(5, 10) zipWithIndex)         yield <item><num>{c}</num><val>{x}</val></item> } </list> Console.println(xml)

[rizzix]

Scala:

class Foo {     private[this] var n = ""     def name = n     def name_=(n : String) =         this.n = if (n == "bar") "baz" else n } val foo = new Foo; foo.name = "bar" Console print foo.name // "baz"

Properties

[wtd]

Let's create our own loop.

code:

def myFor(init: Int, test: Int => Boolean, update: Int => Int)(action: Int => Unit): Unit =    if (test(init)) {       action(init)       myFor(update(init), test, update)(action)    }

And then we'll try calling it.

code:

myFor(1, _ <= 3, _ + 1) {    case n => Console println n }

Or perhaps...

code:

val doFromOneToThree = myFor(1,  _ <= 3, _ + 1) _ doFromOneToThree { case n => Console println n }

[wtd]

Perhaps something inspired by education.

code:

type Name = (String, String) type NameList = List[Name] class MathClass(protected var teachers: NameList, protected var students: NameList) {     def addTeacher(teacher: Name) {         teachers = teachers ::: List(teacher)     }     def addStudent(student: Name) {         students = students ::: List(student)     }     def foreachTeacher(action: Name => Unit) {         for (val teacher <- teachers) action(teacher)     }     def foreachStudent(action: Name => Unit) {         for (val student <- students) action(student)     }     def foreachTeacherStudentCombination(action: (Name, Name) => Unit) {         for (val teacher <- teachers;              val student <- students) action(teacher, student)     } }

code:

val myClass = new MathClass(List(("Foo", "Bar"), ("Baz", "Smith")), List(("Baz", "Qux"), ("Wooble", "Ninja"))) myClass foreachTeacherStudentCombination {     case ((tFirst, tLast), (sFirst, sLast)) =>         if (tFirst == sFirst || tLast == sLast || tFirst == sLast || tLast == sFirst) {             Console println "Whoa!  Similar names.... groovy!"         }         else {             val tName = tFirst + " " + tLast             val sName = sFirst + " " + sLast             Console println (tName + " teaches " + sName + ".")         } }