使用Swift命令行工具进行颜色输出

Question

我正在用Swift编写命令行工具，我在shell中显示颜色时遇到问题。我正在使用以下代码：

println("\033[31;32mhey\033[39;39m")

甚至

NSFileHandle.fileHandleWithStandardOutput().writeData("\033[31;32mhey\033[39;39m".dataUsingEncoding(NSASCIIStringEncoding, allowLossyConversion: true)!)

当我在php中使用一个简单的echo（文本显示为绿色）时，它有效，但是有一个原因它在Swift命令行工具中不起作用吗？

谢谢！

Answer 1

Swift内置了unicode支持。这会使用反斜杠无效。因此我使用带有“\ u {}”语法的颜色代码。这是一个完全适用于终端的println代码。

// \u{001B}[\(attribute code like bold, dim, normal);\(color code)m

// Color codes
// black   30
// red     31
// green   32
// yellow  33
// blue    34
// magenta 35
// cyan    36
// white   37

println("\u{001B}[0;33myellow")

希望能帮助到你。

Answer 2

根据@cyt的回答，我写了一个简单的枚举用这些颜色和重载的+操作符，所以你可以使用该枚举打印。

这都是up on Github，但它真的很简单：

enum ANSIColors: String {
    case black = "\u{001B}[0;30m"
    case red = "\u{001B}[0;31m"
    case green = "\u{001B}[0;32m"
    case yellow = "\u{001B}[0;33m"
    case blue = "\u{001B}[0;34m"
    case magenta = "\u{001B}[0;35m"
    case cyan = "\u{001B}[0;36m"
    case white = "\u{001B}[0;37m"

    func name() -> String {
        switch self {
        case .black: return "Black"
        case .red: return "Red"
        case .green: return "Green"
        case .yellow: return "Yellow"
        case .blue: return "Blue"
        case .magenta: return "Magenta"
        case .cyan: return "Cyan"
        case .white: return "White"
        }
    }

    static func all() -> [ANSIColors] {
        return [.black, .red, .green, .yellow, .blue, .magenta, .cyan, .white]
    }
}

func + (let left: ANSIColors, let right: String) -> String {
    return left.rawValue + right
}

// END


// Demo:

for c in ANSIColors.all() {
    println(c + "This is printed in " + c.name())
}

Answer 3

如果您不介意将其用作框架，则可以使用Rainbow。

import Rainbow
print("Red text".red)
print("Yellow background".onYellow)
print("Light green text on white background".lightGreen.onWhite)

https://github.com/onevcat/Rainbow

Answer 4

结合@ Diego的一些答案，你可以使用Swift的新DefaultStringInterpolation结构将这种装饰扩展到你的字符串文字中 -

enum ASCIIColor: String {
    case black = "\u{001B}[0;30m"
    case red = "\u{001B}[0;31m"
    case green = "\u{001B}[0;32m"
    case yellow = "\u{001B}[0;33m"
    case blue = "\u{001B}[0;34m"
    case magenta = "\u{001B}[0;35m"
    case cyan = "\u{001B}[0;36m"
    case white = "\u{001B}[0;37m"
    case `default` = "\u{001B}[0;0m"
}

extension DefaultStringInterpolation {
    mutating func appendInterpolation<T: CustomStringConvertible>(_ value: T, color: ASCIIColor) {
        appendInterpolation("\(color.rawValue)\(value)\(ASCIIColor.default.rawValue)")
    }
}
// USAGE:
// "\("only this string will be green!", color: .green)"

Answer 5

扩展Diego Freniche's answer我们可以在Uncharted Works's Answer中引用Rainbow的功能，而无需使用简单的String扩展来导入框架本身：

enum ANSIColor: String {

    typealias This = ANSIColor

    case black = "\u{001B}[0;30m"
    case red = "\u{001B}[0;31m"
    case green = "\u{001B}[0;32m"
    case yellow = "\u{001B}[0;33m"
    case blue = "\u{001B}[0;34m"
    case magenta = "\u{001B}[0;35m"
    case cyan = "\u{001B}[0;36m"
    case white = "\u{001B}[0;37m"
    case `default` = "\u{001B}[0;0m"

    static var values: [This] {
        return [.black, .red, .green, .yellow, .blue, .magenta, .cyan, .white, .default]
    }

    static var names: [This: String] = {
        return [
            .black: "black",
            .red: "red",
            .green: "green",
            .yellow: "yellow",
            .blue: "blue",
            .magenta: "magenta",
            .cyan: "cyan",
            .white: "white",
            .default: "default",
        ]
    }

    var name: String {
        return This.names[self] ?? "unknown"
    }

    static func + (lhs: This, rhs: String) -> String {
        return lhs.rawValue + rhs
    }

    static func + (lhs: String, rhs: This) -> String {
        return lhs + rhs.rawValue
    }

}

extension String {

    func colored(_ color: ANSIColor) -> String {
        return color + self + ANSIColor.default
    }

    var black: String {
        return colored(.black)
    }

    var red: String {
        return colored(.red)
    }

    var green: String {
        return colored(.green)
    }

    var yellow: String {
        return colored(.yellow)
    }

    var blue: String {
        return colored(.blue)
    }

    var magenta: String {
        return colored(.magenta)
    }

    var cyan: String {
        return colored(.cyan)
    }

    var white: String {
        return colored(.white)
    }

}