bool.swift

//Turns out in swift Bool is a struct!

/// From the Docs. `import Swift`

/// A value type whose instances are either `true` or `false`.
struct Bool {

    /// Default-initialize Boolean value to `false`.
    init()
}

// This means that if you try to switch on a Bool You must provide a default case. 
switch tooSmallToSort {
    case true: return a
    case false: return a.reduce([a.first!], combine: _uniq)
}

// tooSmallToSort is a Bool, but we get a compiler error at the last brace urging us to add a default case.