Swift Punycode

Swift Punycode is a Swift implementation of the Punycode encoding, as described in RFC 3492.

Punycode is a simple and efficient transfer encoding syntax designed to uniquely and reversibly transforms a Unicode string into an ASCII string. ASCII characters in the Unicode string are represented literally, and non-ASCII characters are represented by ASCII characters.

Usage

Swift Punycode adds two methods to Swift.String.

• String.punycode(delimiter:encodingDigitWith:) encodes a string into Punycode.
• String.init?(punycode:delimiter:decodingDigitWith:) decoes a Punycode string.

For example:

import Punycode

let greetings = "みなさん、こんにちは!"
let encoded = greetings.punycode()
print(encoded) // Prints "!-63t0lg6d7bk7a1ksic"

let decoded = String(punycode: encoded)!
print(decoded) // Prints "みなさん、こんにちは!"

By default, the separator between the literal part and the digits is "-", as specified in RFC 3492. Further, digits are encoded as single characters in base 36 (e.g., 5 => "5", 11 => "b").

Installation

To use the Swift Punycode in a SwiftPM project, add the following line to the dependencies in your Package.swift file:

.package(url: "https://github.com/val-lang/swift-punycode", from: "1.0.0"),

Include "Punycode" as a dependency for your executable target:

.target(name: "<target>", dependencies: [
  .product(name: "Punycode", package: "swift-punycode"),
]),

Finally, add import Punycode to your source code.