Composing NSAttributedString with SwiftUI-style syntax, powered by Result Builder.

Project Link: https://github.com/ethanhuang13/NSAttributedStringBuilder

Traditionally we compose a NSAttributedString like this:

let mas = NSMutableAttributedString(string: "")
mas.append(NSAttributedString(string: "Hello world", attributes: [.font: UIFont.systemFont(ofSize: 24), .foregroundColor: UIColor.red]))
mas.append(NSAttributedString(string: "\n"))
mas.append(NSAttributedString(string: "with Swift", attributes: [.font: UIFont.systemFont(ofSize: 20), .foregroundColor: UIColor.orange]))

Now, with NSAttributedStringBuilder, we can use SwiftUI-like syntax to declare NSAttributedString:

let attributedString = NSAttributedString {
    AText("Hello world")
        .font(.systemFont(ofSize: 24))
        .foregroundColor(.red)
    LineBreak()
    AText("with Swift")
        .font(.systemFont(ofSize: 20))
        .foregroundColor(.orange)
}

Xcode 12.5. This project uses Swift 5.4 feature Result Builder.

Open your project in Xcode 12, navigate to Menu -> Swift Packages -> Add Package Dependency and enter https://github.com/ethanhuang13/NSAttributedStringBuilder to install.

Add pod 'NSAttributedStringBuilder13' to your Podfile.

Besides clearer NSAttributedString syntax, since NSAttributedStringBuilder uses Result Builder it also enables API to build components in UIViewRepresentable(which embeds UIView in a SwiftUI View).

Just like a SwiftUI Text takes a String as input, the purpose of AttributedText in the sample project is to take a NSAttributedString as input and render in SwiftUI.

To achieve this, AttributedText.swift uses @NSAttributedStringBuilder to support SwiftUI-style syntax:

Then using an AttributedText will be like:

Open the sample in /SwiftUISampleApp/AttributedTextSample.xcodeproj and check AttributedText. It uses UITextView, you can also use UILabel or NSTextView.

• Better tests for image attachment

• NSAttributedString does not support link color, therefore Link component with a .color() modifier has no effect. Alternatively you need to specify in UITextView.linkTextAttributes or .tintColor.

Initially discussed on this Twitter thread. Some code are inspired by zonble🙏.