Getting a sequence of lines from a Swift string

LineSequence.swift

import Foundation

let text = """
  Hello
  World
  """

extension String {
  var lines: AnySequence<Substring> {
    let string = self

    return AnySequence { () -> AnyIterator<Substring> in
      var offset = string.startIndex

      return AnyIterator {
        let searchRange = offset..<string.endIndex
        guard !searchRange.isEmpty else { return nil }

        var substring: Substring?

        string.enumerateSubstrings(in: searchRange, options: [.byLines, .substringNotRequired]) { _, line, enclosing, stop in
          substring = string[line]
          offset = enclosing.upperBound
          stop = true
        }

        return substring
      }
    }
  }
}

for line in text.lines {
  print(line)
}