trailing conditionals

implicits.scala

implicit def trailingConditionals[T](any: => T) = new {
  def provided(expr: Boolean) = if (expr) Some(any) else None
  def unless(expr: Boolean) = if (!expr) Some(any) else None
}

implicit def verbosePlus(i: Int) = new {
  def plus(j: Int): Int = {
    println("Adding " + i + " and " + j);
    i + j
  }
}

repl

scala> :load implicits.scala
Loading implicits.scala...
trailingConditionals: [T](any: => T)java.lang.Object{def provided(expr: Boolean): Option[T]; def unless(expr: Boolean): Option[T]}
verbosePlus: (i: Int)java.lang.Object{def plus(j: Int): Int}

scala> println("3 is larger than 1") provided 3 > 1
3 is larger than 1
res0: Option[Unit] = Some(())

scala> println("1 is larger than 3") provided 1 > 3
res1: Option[Unit] = None

scala> 1 plus 3 unless 1 > 3
Adding 1 and 3
res2: Option[Int] = Some(4)

scala> 3 plus 1 unless 3 > 1
res3: Option[Int] = None