Very interesting. I'm surprised that Swift is already expressive enough to support constructs like this. Swift is young enough that it hasn't landed on a parti

Very interesting. I'm surprised that Swift is already expressive enough to support constructs like this. Swift is young enough that it hasn't landed on a particular philosophy yet, and I wonder if it will bend toward ML or more in the direction of Go. For example, protocols and functions currently seem somewhat contradictory; getting the Unicode-compliant length of a string is a function, countElements, not a method, for example. The fact that Swift is both OO and functional (with generics to boot) means there is an inherent conflict in the language that could lead to multiple styles of using it becoming popular. Witness Ruby's stylistic transformation as it became popular and started trends that now make the old standard library seem antiquated by comparison. Or C++'s transformation through the STL. Or Python's engagement with functional programming (which never really was able to transform it away from its OO origins). By comparison, Go is simple and inexpressive, so that it's practically impossible to break style; indeed that seems to be core to Go's philosophy.