anchor.diff:      case get_fbinding(Fun, Ar, Env) of
           {yes,M,F} -> erlang:apply(M, F, eval_list(Es, Env));
           {yes,F} -> eval_apply(F, eval_list(Es, Env), Env);
  -        no -> erlang:error({unbound_func,{Fun,Ar}})
  +        no -> eval_error({unbound_func,{Fun,Ar}})
       end;
   eval_expr([_|_]=S, _) ->                        %Test if string literal
       case is_posint_list(S) of
           true -> S;                              %It an "atomic" type
           false ->                                %It is a bad application form
  -            erlang:error({bad_form,application})
  +            eval_error({bad_form,application})
       end;
   eval_expr(Symb, Env) when is_atom(Symb) ->
       case get_vbinding(Symb, Env) of
           {yes,Val} -> Val;
  -        no -> erlang:error({unbound_symb,Symb})
  +        no -> eval_error({unbound_symb,Symb})
       end;
   eval_expr(E, _) -> E.                           %Atomic evaluate to themselves
   
  
positive.code:             case bit_size(Val) of
              Sz when Sz rem Unit =:= 0 ->
                  <<Val:Sz/bitstring>>;
              _ -> erlang:error(badarg)
              end;
             true ->
              Sz = Eval(Size),
  
negative.code:     P = {map_key(K),eval_expr(V, Env)},
      [P|map_pairs(As, Env)];
  map_pairs([], _) -> [];
  map_pairs(_, _) -> eval_error(badarg).
  
  %% map_key(Key) -> Value.
  %%  Map keys can only be literals.
  