An object initialisation operator in Swift

RocketOperator.swift

infix operator => { associativity left precedence 100 }
infix operator =>? { associativity left precedence 100 }

/// Perform side effects on `x` and then return it. Example:
///
///     self.label = UILabel(frame: frame) => { l in
///         l.text = "Hello?"
///     }
func =><T>(x: T, f: T -> ()) -> T {
    f(x)
    return x
}

func =>?<T>(x: T?, f: T -> ()) -> T? {
    if let y = x { f(y) }
    return x
}