bmarcot

case class Order(val id: Int, val card: Int, val address: String)

// val m = (for (i <- 1 to 4) yield Order(i)) zip List(1, 1, 2, 3)
// m.groupBy(_._2)

val orders = (for {
  order <- List(Order(1, 46459, "3, calle Brazil, Torremolinos"),
                Order(2, 85475, "102, av JB Clement, Boulogne"),
                Order(1, 78545, "1, Paradize Bvld., Palo Alto"))
} yield (order, order.id))

bmarcot

def f(xs: List[Int]): List[List[(Int, Int)]] = {
  xs match {
    case Nil => List(List()) 
    case x :: xs => for {
      ns <- f(xs)
      i <- 0 to x
      } yield (x, i) :: ns
  }
}

bmarcot

def queens(n: Int): Set[List[Int]] = {
  
  def isSafe(col: Int, queens: List[Int]): Boolean = {
    val row = queens.length
    val queensWithRow = queens zip (row - 1 to 0 by -1)
    queensWithRow.forall {
      case (c, r) => c != col && (math.abs(col - c) != row - r)
    }
  }
  

bmarcot

def ScalarProduct(xs: List[Double], ys: List[Double]): Double =
  (for ((x, y) <- xs zip ys) yield x * y).sum

bmarcot

def isPrime(n: Int): Boolean = (2 to n - 1).forall(x => n % x != 0)

bmarcot

def mapFun[T, U](xs: List[T], f: T => U): List[U] = (xs foldRight List[U]())(f(_) :: _)

bmarcot

def squareList(xs: List[Int]): List[Int] = xs match {
  case Nil     => Nil
  case y :: ys => y * y :: squareList(ys)
}
  
def squareList(xs: List[Int]): List[Int] = xs map (y => y * y)

bmarcot

Then /I should see "(.*)" before "(.*)"/ do |e1, e2|
  #  ensure that that e1 occurs before e2.
  #  page.body is the entire content of the page as a string.
  assert page.body.index(e1) < page.body.index(e2)
end

Then /I should see "(.*)" before "(.*)"/ do |e1, e2|
  #  another strategy with regex (see Hints part of the assignments)
  page.body.scan(/.*"#{e1}".*"#{e2}".*/).length.should == 1
end

bmarcot

// Peano numbers

abstract class Nat {
  def isZero: Boolean
  def predecessor: Nat
  def successor: Nat = new Succ(this)
  def + (that: Nat): Nat
  def - (that: Nat): Nat
}

bmarcot

object List {
  // List()
  def apply[T]() = new Nil
  
  // List(1)
  def apply[T](x1: T): List[T] = new Cons(x1, new Nil)
  
  // List(1, 2)
  def apply[T](x1: T, x2: T): List[T] = new Cons(x1, new Cons(x2, new Nil))
}