Function composition in Swift

FunctionComp.swift

operator infix .. {
associativity right
}

func ..<A, B, C>(f: B -> C, g: A -> B)  -> A -> C {
    return { (a: A) -> C in
        return f(g(a))
    }
}

let array = [1,2,3,4]
let mapped = array.map({$0 + 1} .. {$0 + 1} .. {$0 + 1})
mapped // [4,5,6,7]