anchor.diff:      {Exp,St1} = exp_nequal(Es, Op, St0),
       {yes,Exp,St1};
   exp_predef([Op|Es], _, St0)
  -  when Op == '>'; Op == '>='; Op == '<'; Op == '=<';
  -       Op == '=='; Op == '=:=' ->
  +  when Op =:= '>'; Op =:= '>='; Op =:= '<'; Op =:= '=<';
  +       Op =:= '=='; Op =:= '=:=' ->
       case Es of
           [_|_] ->
               {Exp,St1} = exp_comp(Es, Op, St0),
  
positive.code:     ['if',Test,?Q(true),exp_cond(Cond)];
  exp_cond([]) -> ?Q(false).
  
  %% exp_andalso(AndAlsoBody) -> Ifs.
  %% exp_orelse(OrElseBody) -> Ifs.
  
  
negative.code: 
  defspec_arity([[Args|_]|_]) ->
      case lfe_lib:is_proper_list(Args) of
          true -> length(Args);
          false -> 0
      end;
  defspec_arity(_) -> 0.
  
  