Extension to convert markdown String to NSAttributedString with links ready to use in UITextView

String+MarkdownLinks.swift

//
//  String+MarkdownLinks.swift
//
//  Copyright © 2018 Evgeny Aleksandrov. MIT License.

import Foundation

extension String {

    func parseMarkdownLinks() -> NSMutableAttributedString {
        let pattern = "\\[([^\\]]+)\\]\\(([^\\)\"\\s]+)(?:\\s+\"(.*)\")?\\)"
        guard let regex = try? NSRegularExpression(pattern: pattern, options: []) else { return NSMutableAttributedString(string: self) }

        let attributedText = NSMutableAttributedString(string: self)
        let numberOfLinksFound = regex.numberOfMatches(in: self, options: [], range: NSRange(location: 0, length: self.count))

        for _ in 0..<numberOfLinksFound {
            let textToParse = attributedText.string
            if let match = regex.firstMatch(in: textToParse, options: [], range: NSRange(location: 0, length: textToParse.count)), match.numberOfRanges > 2 {
                let matchRange = match.range
                let linkRange = match.range(at: 1)
                let urlRange = match.range(at: 2)

                let linkAttributedStr = NSAttributedString(string: (textToParse as NSString).substring(with: linkRange), attributes: [NSAttributedString.Key.link: (textToParse as NSString).substring(with: urlRange)])

                attributedText.replaceCharacters(in: matchRange, with: linkAttributedStr)
            }
        }

        return attributedText
    }
}