OleTraveler

trait PaymentSource {
  def accept[T](visitor: PsVisitor[T]) : T
}

class CreditCard extends PaymentSource{
  override def accept[T](visitor: PsVisitor[T]) = {
    visitor.visit(this)
  }
}

OleTraveler

def maxTen(i: Int) =
  if (i <= 10) \/-(i)
  else "Must be less than ten"
  
def divisibleByTwo(i: Int) = 
  if (i % 2 == 0) == 0 \/-(i)
  else "Must be divisable by two"
  
def whatType(input: Int): ???[NonEmptyList[String], Int] = 
  ( parseInt(input) |@| divisibleByTow(input) )

OleTraveler

package com.czarism.blog

import scalaz._
import Scalaz._

/**
 * Created by tstevens on 7/18/14.
 */

object FavorValidation {

OleTraveler

  /** Determine if the list l contains a sequence which follows the recurrence relation for the function f.
    *
    * A recurrence relation is where numbers in the list determine the rest of the list, for example the Fibonacci sequence
    * is defined for function plus and you could call this function with the parameters l = List(0,1,1,2,3,5,8,13), f = _ + +
    *
    *  See InterviewSpec for a test example.
    * */
  def isRecurrenceRelation(l: List[Int], f: (Int, Int) => Int) : Boolean = ???