lazy

gistfile1.scala

trait Lazy[T] {
  def value: T
  def map[U](f: T => U): Lazy[U]
  def flatten[U](implicit lazyConv: (=> T) => Lazy[U]): Lazy[U]
  def flatMap[U](f: T => Lazy[U]): Lazy[U]
}

object Lazy {
  implicit def lazyIdentity[A]: (=> Lazy[A]) => Lazy[A] = (old) => Lazy { old.value }

  def apply[T](t: => T): Lazy[T] = new Lazy[T] {
    lazy val value = t
    def map[U](f: T => U): Lazy[U] = Lazy(f(t))
    def flatten[U](implicit lazyConv: (=> T) => Lazy[U]): Lazy[U] =
      lazyConv(t)
    def flatMap[U](f: T => Lazy[U]): Lazy[U] = map(f).flatten
  }
}