cgopalan

object ListMap {
  def squareList(xs: List[Int]): List[Int] = xs match { 
    case List() => xs
    case y :: ys => y * y :: squareList(ys)
  } 
  def squareListMap(xs: List[Int]): List[Int] = 
    xs map (x => x * x)
  
  def main(args: Array[String]) {
    println("squarelist for square of (9,13,21) returns : " + squareList(List(9, 13, 21)));

cgopalan

object ListFilter {
  def forall(xs: List[Int], p: Int => Boolean): Boolean = 
     xs.isEmpty || xs.filter(p) == xs
  def exists(xs: List[Int], p: Int => Boolean): Boolean = 
    !xs.isEmpty && !xs.filter(p).isEmpty
    
  def main(args: Array[String]) {
    println("Are members of list (1,2,3,4,5) less than 10? : " + 
    									forall(List(1,2,3,4,5), (x => x < 10)));
    println("Is there at least one member of list (1,2,3,4,5) thats greater than 5? : " + 

cgopalan

object NQueensProblem {
   def queens(n: Int): List[List[Int]] = {
      def placeQueens(k: Int): List[List[Int]] =
         if (k == 0) List(List())
         else for { queens <- placeQueens(k - 1)
                     column <- List.range(1, n + 1)
                     if isSafe(column, queens, 1)} yield column :: queens
      placeQueens(n)
   }
   def isSafe(col: Int, queens: List[Int], delta: Int): Boolean = queens match {

cgopalan

object ForToMap {
   def main(args: Array[String]) {
      case class Book(title: String, authors: List[String])
      val books: List[Book] = List(
         Book("Structure and Interpretation of Computer Programs",
         List("Abelson, Harold", "Sussman, Gerald J.")),
         Book("Principles of Compiler Design",
         List("Aho, Alfred", "Ullman, Jeffrey")),
         Book("Programming in Modula2",
         List("Wirth, Niklaus")),

cgopalan

object FunctionalLoops {
   def repeatLoop(command: => Unit)(condition: => Boolean) {
      command
      if (condition) {
         repeatLoop(command)(condition)
      } else ()
   }

   def repeatUntilLoop(command: => Unit) = {
      class RepeatUntilLoopClass(command: => Unit) {

cgopalan

object SimpleOrGate {
   type Action = () => Unit
   
   class Wire {
      private var sigVal = false
      private var actions: List[Action] = List()
      def getSignal = sigVal
      def setSignal(s: Boolean) =
         if (s != sigVal) {
         sigVal = s

cgopalan

object CompoundOrGate {
   type Action = () => Unit
   
   class Wire {
      private var sigVal = false
      private var actions: List[Action] = List()
      def getSignal = sigVal
      def setSignal(s: Boolean) =
         if (s != sigVal) {
         sigVal = s

cgopalan

import rlcompleter, readline
readline.parse_and_bind('tab: complete')

cgopalan

def mergesort(arr, n):
    if n == 1: return arr
    len_half = int(n/2)
    return merge(mergesort(arr[:len_half], len_half),
            mergesort(arr[len_half:], n - len_half), n)

def merge(arr1, arr2, n):
    result = []
    i,j = 0,0
    for x in range(n):

cgopalan

"""
    Search for a text in all repos for an organization.
    Currently via the web UI you can only search per repo.

    This will only return number of matches for the text and not
    the filenames (as of now).

    You need an OAuth Token for this to work.

    Run it as: