function option chaining

// Define an optional chaining pipeline operator
operator infix |> { associativity left }
func |> <T, U>(t: T?, f: (T) -> U? ) -> U? {
    if let t1 = t { return f( t1 ) }
    else { return nil }
}

// some dummy classes and functions to chain together
class C { let x = 7 }
class B { }
class A { }
func getB( a : A ) -> B? { return B() }
func getC( b : B ) -> C? { return C() }


let x = ( A() |> getB |> getC )?.x

println("x: \(x)")