(* Author: Carsten Schuermann *)
(* The classical Circuit datastructure *)

datatype Circuit  
  = NOTGate  of Circuit
  | NANDGate of Circuit * Circuit
  | ANDGate  of Circuit * Circuit
  | NORGate  of Circuit * Circuit
  | ORGate   of Circuit * Circuit
  | XORGate  of Circuit * Circuit
  | SIGNAL   of BOOL