some String manipulations

Abstract - StringManipulationOperators.md

String manipulation operators

let fiveTimesHello = 5 * "hello" // "hellohellohellohellohello"
let helloPlus5 = "hello" + 5 // "hello5"

StringManipulation.swift

func * (left: UInt, right: String) -> String {
    var res = right
    res *= left
    return res
}

func * (left: String, right: UInt) -> String {
    var res = left
    res *= right
    return res
}

func *= ( left: inout String, right: UInt) -> String {
    if right == 0 {
        left = ""
        return left
    }
    let orig = left
    if right < 5 {
        for _ in 1..<right {
            left += orig
        }
        return left
    }
    let half = right / 2
    let m = left * half
    left = m + m
    if (right & 1 == 1) {
        left += orig
    }
    return left
}

func +<T>(left: String, right: T) -> String {
    return "\(left)\(right)"
}

func +<T>(left: T, right: String) -> String {
    return "\(left)\(right)"
}