Lenses in Swift

Brandon Williams gives a talk at the Functional Swift Conference about Lenses and Prisims in Swift. I’m not 100% sold on their particular usefulness in Swift (and, to be fair, Brandon isn’t either). But I love Brandon’s playground presentations, and this one demonstrates an awesome blueprint for adding expressive, functional constructs to Swift: define a function, genericize it, compose it, and define an operator for the composition.