functor SwMachine (structure Trace : TRACE
		   structure AbsMachine : ABSMACHINE
		   structure TMachine : ABSMACHINE
		   sharing TMachine.IntSyn = AbsMachine.IntSyn
		   sharing TMachine.CompSyn = AbsMachine.CompSyn) : ABSMACHINE =
struct

  structure IntSyn = AbsMachine.IntSyn
  structure CompSyn = AbsMachine.CompSyn

  fun solve args =
    if Trace.tracing ()
      then TMachine.solve args
    else  AbsMachine.solve args

end;  (* functor SwMachine *)