automaton__destination Function

   pure function automaton__destination(self, curr, symbol) result(ret)
      use :: forgex_lazy_dfa_node_m, only: dfa_transition_t
      implicit none
      class(automaton_t),    intent(in) :: self
      integer(int32),        intent(in) :: curr
      character(*),          intent(in) :: symbol

      type(dfa_transition_t) :: ret

      
      integer :: i

      ! Get a set of NFAs for which current state can transition, excluding epsilon-transitions.
      ret%nfa_set = self%get_reachable(curr, symbol)

      ! Initialize the next value
      ret%dst = DFA_INVALID_INDEX

      ! Scan the entire DFA nodes.
      do concurrent (i = 1:self%dfa%dfa_top-1)
         ! If there is an existing node corresponding to the NFA state set,
         ! return the index of that node.
         if (equivalent_nfa_state_set(ret%nfa_set, self%dfa%nodes(i)%nfa_set)) then
            ret%dst = i
         end if
      end do

   end function automaton__destination