@judofyr honestly I don't really understand Glushkov's construction. I don't even quite understand how the paper I read that name in actually corresponds to Glushkov's construction, but it claims that it does, so I guess I have to believe it? https://sebfisch.github.io/haskell-regexp/regexp-play.pdf
@jamey I grokked the logic behind the local language (L'), but I must admit I don't quite know why/how that automaton is easy to construct. or why you need to rename the alphabet first.