Looking at this article ... https://www.codeproject.com/Articles/21080/In-Depth-with-RegEx-Matching-Nested-Constructions, where it says The Push-down Automata roughly 1/4 way down, although am not sure the same will be using Swift. Apparently using (?<S>Agora)(?(S)(?!)|(.*)) should work but does not.
Any suggestions for using conditional group ?
