anchor.diff:    (assert (internal-state-p state))
     (setf (cddr state) new-transitions))
   
  -(defun make-final-state (tag)
  -  (list* :final nil tag))
  +(defun make-final-state (action)
  +  (list* :final nil action))
   
   (defun final-state-p (state)
     (eq (car state) :final))
   
  -(defun state-tag (state)
  +(defun state-action (state)
     (assert (final-state-p state))
     (cddr state))
   
  
positive.code: ;;;     information for each state of the layer.
  ;;;
  ;;;   * If the state is a final state, then the information of the
  ;;;     state is represented as a CONS of the NAME and the TAG of the
  ;;;     state.
  ;;;
  ;;;   * If the state is an internal state, then the information of the
  ;;;     state is represented as a CONS of the NAME of the state and a
  
negative.code: ;;; We represent the automaton as nested lists.  We deliberately avoid
  ;;; using classes so as to avoid circular dependencies.
  
  ;;; A STATE of the automaton is either a FINAL state or an INTERNAL
  ;;; state.  A final state has no transitions associated with it, and
  ;;; instead it has a ACTION.  Final states with identical (EQ) actions
  ;;; are considered equivalent.  An internal state has a list of
  ;;; transitions associated with it.  During construction of the
  ;;; automaton, some internal states may have an empty list of
  ;;; transitions, but in the final automaton, every internal state has
  ;;; a non-empty list of transitions associated with it.  There can
  ;;; never be two transitions in a state with the same label (see
  ;;; below).  Two internal states with the same set of transitions
  ;;; (same number of transitions, same labels, leading to equivalent
  ;;; states) are considered equivalent.  A state is represented as two
  ;;; CONS cells.  The CAR of the first cell contains either :INTERNAL
  ;;; or :FINAL according to whether the state is an internal or a final
  ;;; state.  The CAR of the second cell is initially NIL and will later
  ;;; be used to hold a GENSYMed NAME of the state.  If the state is a
  ;;; final state, then the CDR of the second CONS cell contains the
  ;;; action.  If the state is an internal state, the CDR of the second
  ;;; CONS cell contains the list of transitions.
  
  ;;; FIXME: We are using the following standard Common Lisp functions
  ;;; that are defined to work on sequences, rather than just lists:
  