HumanString

HumanString is a package that let you use integers but not String.Index to specify ranges in strings.

let str = "今天天氣好清爽"
XCTAssertTrue(str[0] == "今")
XCTAssertTrue(str[4] == "好")
XCTAssertTrue(str[-1] == "爽")
XCTAssertTrue(str[0..<2] == "今天")
XCTAssertTrue(str[0...2] == "今天天")
XCTAssertTrue(str[-3 ..< -1] == "好清")
XCTAssertTrue(str[-3 ... -1] == "好清爽")
XCTAssertTrue(str[-3 ... 0] == nil)
XCTAssertTrue(str[-3 ..< 0] == "好清爽")
XCTAssertTrue(str[-3 ..< 1] == nil)
XCTAssertTrue(str[-3 ... 1] == nil)
XCTAssertTrue(str[0...] == "今天天氣好清爽")
XCTAssertTrue(str[1...] == "天天氣好清爽")
XCTAssertTrue(str[(-2)...] == "清爽")
XCTAssertTrue(str[(-1)...] == "爽")
XCTAssertTrue(str[..<3] == "今天天")
XCTAssertTrue(str[...3] == "今天天氣")
XCTAssertTrue(str[..<(-1)] == "今天天氣好清")
XCTAssertTrue(str[...(-1)] == "今天天氣好清爽")

Installation

You can install the package using Swift package manager. Add the following lines to your Packages.swift file:

dependencies: [
    .package(url: "https://github.com/zonble/HumanString.git"),
],

You can also install the library using CocoaPods, just add pod "HumanString" to you Podfile.

Notes

Swift adopts String.Index since Swift 4. It tends to reminder you that the width of a string is not fixed (SeeStrings in Swift 4). However, it is somehow painful. For example, if you want to extract a prefix from “Hello World”, it could be:

let str = "Hello World"
let subString = s[...str.index(str.startIndex, offsetBy: 5)]

But wait, somehow you are still using integers, right? The code above could be written as:

let subString = s[str.index(str.startIndex, offsetBy: 0)...str.index(str.startIndex, offsetBy: 5)]

I know the Swift team does not like what I am doing here, but somehow I still want to make my life easier.