Delightful console output for Swift developers.

Hey there. I'm trying to build a string similar to a Powerline prompt.

It's a series of segments, separated by a custom powerline triangle glyph. The glyph is coloured predicably: the triangle part of is coloured based on the text colour, and the background is coloured based on the background. But the glyph exists to connect two different background colours.

This means you want to set its text colour to the equivalent of the background colour of whats to the left, and the background colour to be equal to the background colour of whats to the right. To achieve this, you need a way of converting a BackgroundColor to its Color counterpart.

Here's my example:

import Rainbow

extension BackgroundColor {
	var toTextColor: Color {
		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
		case .default:	return .default
		}
	}
}

struct Segment {
	let text: String
	let textColor: Color = .default
	let backgroundColor: BackgroundColor
}

extension Collection where Element == Segment {
	func joined() -> String {
		let dummySegment = Segment(text: "", backgroundColor: .default)
		
		let strings = zip(self, self.dropFirst() + [dummySegment]).map { current, next -> String in
			let separator = "".applyingCodes(current.backgroundColor.toTextColor, next.backgroundColor)
			let text = current.text.applyingCodes(current.textColor, current.backgroundColor)
			return text + separator
		}
		
		return strings.joined()
	}
}

let segments = [
	Segment(text: "abc", backgroundColor: .red),
	Segment(text: "def", backgroundColor: .green),
	Segment(text: "ghi", backgroundColor: .blue),
]

let result = segments.joined() + " The rest of the message"

print("before\n")
print(result)
print("\nafter")

Output (rendered in SF mono nerd font:

I wanted to contribute the implementation of toTextColor, because I think it might be useful to others. The reverse direction might also be useful, though there are more Colors than can map onto BackgroundColors, so its unclear how to handle the unmappable cases (make the computed property optional and return nil?)

Do you think this would be useful for me to contribute?

If so, how do you think I should write the test for it?

Updated code to work with Swift 3.0-dev 2016-05-09 development snapshot. There should be a 3.0 public release candidate coming up in the next few weeks, might want to merge then (since this will probably break all 2.2 builds).

Would also love some feedback, this is my first contribution to open source 🔥

My logs are still black. When I set Environment Variable "XcodeColors" to YES, my output is like this: g255,0,0;Recognized a double tap[;

I followed the directions in the readme file and while I'm able to see Rainbow install when I add the .package(url: "https://github.com/onevcat/Rainbow", from: "3.0.0") line to the dependencies array, I get No such module Rainbow when I attempt to import it in main.swift.

I tried adding it to targets, too, like so:

    targets: [
        .target(
            name: "MyCLIUtility",
            dependencies: ["SPMUtility", "Rainbow"]),
        .testTarget(
            name: "MyCLIUtilityTests",
            dependencies: ["MyCLIUtility"]),
    ]

What am I missing?

Use of String.character is now unnecessary as String is a sliceable collection all its own in Swift 4. This patch removes accesses to the characters collection and, in doing so, silences the warnings for its usage that appear in Xcode 9.1.

Using Xcode 7.3 cocopods. I added Rainbow in the Podfile per your README. I also remembered to import RaindobowSwift (vs Rainbow). Now, when I try to use it, type-ahead shows me the colors so I know the class is being read. However, no text comes out colored. (ie print("hello myself".red) just prints "hello myself" in the normal console color. I feel like xcode is somehow overriding the coloring maybe.

Ideas?

PS I am in a bridged obj-c/swift project if that's a clue. However, I am only trying this from the Swift side without luck...

The inconsistency in naming (Rainbow / RainbowSwift) makes it difficult to build the same project using Xcode and SPM, without editing imports to one or the other.

First of all, thank you for putting together this library. It's great work!

I share your motivation that Swift will become incredibly useful for command line programs. This is the reason that I started SwiftyTextTable to better organize complex console output.

I think our libraries are a natural pair, and I would like to make them work seamlessly together. Unfortunately, right now the escape sequences that Rainbow uses to inject color and style information are not compatible with my (rather naive) method of calculating string lengths to determine column widths. This is being tracked in this issue: scottrhoyt/SwiftyTextTable#5.

It would be my preference to not introduce a dependency on Rainbow to keep the library as lightweight as possible. Therefore I was wondering if you could assist me in designing an algorithm to strip Rainbow styles and colors from a string for length calculations. From my light reading of the extraction methods already present in Rainbow, it looks like I can detect the presence of a formatted string, and if necessary, apply a regex to extract the text information out of the style information, but I would like to hear your thoughts on implementation. Thanks!

Hello,

This simple code has an unexpected result:

print(("a" + "b".underline + "c").lightGreen)

I would expect the whole string to be in green, and the b only to be underlined, however the underlining doesn't get reset, so the c gets underlined too!

Expected result: \e[92ma\e[92;4mb\e[0;92mc\e[0m Actual result: \e[92ma\e[92;4mb\e[92mc\e[0m

This happens with all styles when applied to a substring where a foreground color is inherited.

Wei, thanks for your contribution to this project, my new tool relies on it strongly.

After upgrading to the new version 4.0.0, I use the following code to join a colorful message in terminal console, but got something unexpected results:

import RainbowSwift

let entry = Rainbow.Entry(
    segments: [
        .init(text: "Hello ", color: .named(.magenta)),
        .init(text: "Rainbow ", color: .bit8(214), backgroundColor: .named(.black), styles: [.underline]),
        .init(text: "Hello ", color: .named(.magenta)/*, backgroundColor: .named(.default)*/),  // Comment 1
        .init(text: "again", color: .named(.magenta), backgroundColor: .named(.red)/*, styles: [.default]*/),  // Comment 2
    ]
)
print(Rainbow.generateString(for: entry))

It shows the black background and styles from the second segment on the second Hello, this is weird, the underline style also affects to the last segment:

If I uncomment the Comment 1 only:

If I uncoment the Comment 2 only:

Uncomment both:

I really don't know how to explain them even after trying to look into the Rainbow inside, please confirm is it a bug or how should I use the Segment. Thanks!

In my command line tool, when I add > filename.txt to output results in a file, it creates an empty file. The output is provided in the console though.

See more details: https://github.com/rsrbk/GoSwifty/issues/3