sign := *top* & 
[ CAT cat].


cat := *top*.
complex-cat := cat &
[ RESULT sign,
  DIRECTION direction,
  ACTIVE sign ].

s := cat.
np := cat.
n := cat.

direction := *top*.
backward := direction.
forward := direction.

phrase := sign &
[ ARGS *list*].

word := sign &
[ ORTH string ].

;;;;;;;;;;;;;;;;;;;;;;;

string := *top*.

*list* := *top*.

*ne-list* := *list* &
 [ FIRST *top*,
   REST *list* ].

*null* := *list*.