MikTeX 2.8不为pdfLaTeX添加连字支持(MikTeX 2.8 doesn't add hyphenation support for pdfLaTeX)

 引用的PHP函数返回一个字符串，其中包含源字符串中每个UTF-8代码单元的3位十进制数字。 在斯威夫特那将是 
 
func toNumbers(_ s: String) -> String {
    return s.utf8.map { String(format: "%03d", $0) }.joined()
}
 
 反向转换有点复杂，因为Swift没有与PHP str_split()对应的内置函数。 我们必须以3为步长迭代索引，并将每个切片转换为一个字节： 
 
func backToString(_ n: String) -> String? {
    var utf8 = Data()
    var from = n.startIndex
    while from < n.endIndex {
        guard let to = n.index(from, offsetBy: 3, limitedBy: n.endIndex) else { return nil }
        guard let u = UInt8(n[from..<to]) else { return nil }
        utf8.append(u)
        from = to
    }
    return String(data: utf8, encoding: .utf8)
}
 
 该函数返回一个可选项，因为转换可能会失败。 
 
 用法示例： 
 
let s = "Wörks wíth all ストリングズ"
let n = toNumbers(s)
print(n) // 087195182114107115032119195173116104032097108108032227130185227131136227131170227131179227130176227130186
if let s2 = backToString(n) {
    print(s2) // Wörks wíth all ストリングズ
}
 
 而且只是为了好玩：第二个功能的更紧凑版本： 
 
func backToString(_ n: String) -> String? {
    return String(bytes: sequence(state: n.startIndex, next: { (from: inout String.Index) -> UInt8?  in
        guard let to = n.index(from, offsetBy: 3, limitedBy: n.endIndex) else { return nil }
        defer { from = to }
        return UInt8(n[from..<to])
    }), encoding: .utf8)
}

The referenced PHP function returns a string with 3 decimal digits for each UTF-8 code unit in the source string. In Swift that would be
 
func toNumbers(_ s: String) -> String {
    return s.utf8.map { String(format: "%03d", $0) }.joined()
}
 
The reverse conversion is a bit more complicated because Swift has no built-in function which corresponds to the PHP str_split(). We have to iterate over the indices in steps of 3, and convert each slice to a byte:
 
func backToString(_ n: String) -> String? {
    var utf8 = Data()
    var from = n.startIndex
    while from < n.endIndex {
        guard let to = n.index(from, offsetBy: 3, limitedBy: n.endIndex) else { return nil }
        guard let u = UInt8(n[from..<to]) else { return nil }
        utf8.append(u)
        from = to
    }
    return String(data: utf8, encoding: .utf8)
}
 
The function returns an optional because the conversion can fail.
 
Example usage:
 
let s = "Wörks wíth all ストリングズ"
let n = toNumbers(s)
print(n) // 087195182114107115032119195173116104032097108108032227130185227131136227131170227131179227130176227130186
if let s2 = backToString(n) {
    print(s2) // Wörks wíth all ストリングズ
}
 
And just for fun: a more compact version of the second function:
 
func backToString(_ n: String) -> String? {
    return String(bytes: sequence(state: n.startIndex, next: { (from: inout String.Index) -> UInt8?  in
        guard let to = n.index(from, offsetBy: 3, limitedBy: n.endIndex) else { return nil }
        defer { from = to }
        return UInt8(n[from..<to])
    }), encoding: .utf8)
}