structure AllDfa =
struct
  type t = {curInt: int, curSpace: int, curBrace: int, lastInt: int,
  lastSpace: int, lastBrace: int}

  val initial: t =
    {
      curInt = IntDfa.start,
      curSpace = SpaceDfa.start,
      curBrace = BraceDfa.start,

      lastInt = ~1,
      lastSpace = ~1,
      lastBrace = ~1
    }

  fun areAllDead ({curInt, curSpace, curBrace, ...}: t) =
    curInt = 0 andalso curSpace = 0 andalso curBrace = 0

  fun update (chr, dfa, pos) =
    let
      val {curInt, curSpace, curBrace, lastInt, lastBrace, lastSpace} = dfa

      val curInt = IntDfa.next (curInt, chr)
      val curSpace = SpaceDfa.next (curSpace, chr)
      val curBrace = BraceDfa.next (curBrace, chr)

      val lastInt = if IntDfa.isFinal curInt then pos else lastInt
      val lastSpace = if SpaceDfa.isFinal curSpace then pos else lastSpace
      val lastBrace = if BraceDfa.isFinal curBrace then pos else lastBrace
    in
      {curInt = curInt, curSpace = curSpace, curBrace = curBrace, lastInt =
      lastInt, lastBrace = lastBrace, lastSpace = lastSpace}
    end
end