ARMarkdownTextStorage

A lightweight Swift library for live markdown-style highlighting and parsing in iOS apps, built on top of NSTextStorage.

Features

• Live highlighting via MarkdownTextStorage — attach to any UITextView for real-time styling without removing markup characters
• Static parsing via MarkdownParser — convert a markdown string into NSAttributedString with markup characters stripped
• Combinable styles (e.g. bold + italic in the same range)
• Optional text truncation with "..." suffix
• Disable highlighting for a specific text by prefixing it with @@

Supported Syntax

Style	Markup	Example
Bold	**text**	**hello**
Italic	__text__	__hello__
Strikethrough	~~text~~	~~hello~~
Underline	```text```	```hello```

Requirements

• iOS 13.0+
• Swift 5.10+
• Xcode 15+

Installation

Swift Package Manager

In Xcode, go to File > Add Package Dependencies… and enter the repository URL:

https://github.com/AppleArealidea/ARMarkdownTextStorage.git

Or add it to your Package.swift dependencies:

dependencies: [
    .package(url: "https://github.com/AppleArealidea/ARMarkdownTextStorage.git", from: "1.0.0")
]

Then add "ARMarkdownTextStorage" to the dependencies of your target.

Usage

Live Highlighting with UITextView

Use MarkdownTextStorage to add real-time markdown highlighting to a UITextView. Markup characters remain visible in the text while their content is styled.

import ARMarkdownTextStorage

let font = UIFont.systemFont(ofSize: 16)
let textStorage = MarkdownTextStorage(font: font)

let layoutManager = NSLayoutManager()
textStorage.addLayoutManager(layoutManager)

let textContainer = NSTextContainer(size: view.bounds.size)
layoutManager.addTextContainer(textContainer)

let textView = UITextView(frame: view.bounds, textContainer: textContainer)
view.addSubview(textView)

To update the base font later:

textStorage.setDefaultFont(UIFont.systemFont(ofSize: 20))

Parsing Markdown to NSAttributedString

Use MarkdownParser to convert a markdown string into a styled NSAttributedString with all markup characters removed.

import ARMarkdownTextStorage

let input = "**Bold** and __italic__ with ~~strikethrough~~"
let font = UIFont.systemFont(ofSize: 16)

let (attributedString, isTruncated) = MarkdownParser.attributedString(
    fromMarkdown: input,
    font: font
)

With optional text color and max length:

let (attributedString, isTruncated) = MarkdownParser.attributedString(
    fromMarkdown: input,
    font: font,
    color: .label,
    maxSymbolsCount: 100
)

License

This project is available under the MIT license. See the LICENSE file for details.