ViewController.swift

let textView = TokenTextView(frame: .zero)
textView.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(textView)
NSLayoutConstraint.activate([
    textView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor, constant: 16),
    textView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor, constant: -16),
    textView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 16),
    textView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: -16)
])
        
let string = "The quick brown fox jumps over the lazy dog"
let attributedString = NSMutableAttributedString(string: string)
let value = "value"
attributedString.addAttribute(.token, value: value, range: NSRange(location: 4, length: 5))
textView.attributedText = attributedString