implicit views

gistfile1.scala

scala> :pa
// Entering paste mode (ctrl-D to finish)

trait Run {
  def run(): Unit
}

def doRun(r: Run) = r.run()

// Exiting paste mode, now interpreting.

defined trait Run
doRun: (r: Run)Unit

scala> doRun(println("hello world"))
<console>:10: error: type mismatch;
 found   : Unit
 required: Run
              doRun(println("hello world"))
                           ^

scala> :pa
// Entering paste mode (ctrl-D to finish)

implicit def blockToRun(b: => Unit) = new Run {
  def run() = b
}

// Exiting paste mode, now interpreting.

warning: there were 1 feature warning(s); re-run with -feature for details
blockToRun: (b: => Unit)Run

scala> doRun(println("hello world"))
hello world

scala> doRun(() => println("hello world"))
<console>:11: error: type mismatch;
 found   : () => Unit
 required: Run
              doRun(() => println("hello world"))
                       ^

scala> :pa
// Entering paste mode (ctrl-D to finish)


implicit def funcToRun(f: () => Unit) = new Run {
  def run() = f()
}

// Exiting paste mode, now interpreting.

warning: there were 1 feature warning(s); re-run with -feature for details
funcToRun: (f: () => Unit)Run

scala> doRun(() => println("hello world"))
hello world