anchor.diff:  
   check_args(Args, Env, L, St) ->
       check_foreach(fun (A, S) -> check_expr(A, Env, L, S) end,
  -          fun (S) -> add_error(L, bad_args, S) end,
  -          St, Args).
  +                  fun (S) -> add_error(L, bad_args, S) end,
  +                  St, Args).
   
   %% check_args(Args, Env, L, St) ->
   %%     case is_proper_list(Args) of
  -%%     true -> check_exprs(Args, Env, L, St);
  -%%     false -> add_error(L, bad_args, St)
  +%%         true -> check_exprs(Args, Env, L, St);
  +%%         false -> add_error(L, bad_args, St)
   %%     end.
   
   %% check_exprs(Exprs, Env, Line, State) -> State.
  
positive.code:     {Fs,St1} = check_fbindings(Fbs, St0),
      %% Now check function definitions.
      St2 = foldl(fun ({_,[lambda|Lambda],L}, St) ->
              check_lambda(Lambda, Env0, L, St);
              ({_,['match-lambda'|Match],L}, St) ->
              check_match_lambda(Match, Env0, L, St)
          end, St1, Fbs),
      %% Add to environment
      Env1 = foldl(fun ({F,A}, Env) -> add_fbinding(F, A, Env) end, Env0, Fs),
      {Fs,Env1,St2}.
  
negative.code: 
  check_fbindings(Fbs0, St0) ->
      AddFb = fun(F, Fs, L, St) ->
                      case member(F, Fs) of
                          true -> {Fs,add_error(L, {redef_fun,F}, St)};
                          false -> {add_element(F, Fs),St}
                      end
              end,
      Check = fun ({V,[lambda,Args|_],L}, {Fs,St}) ->
                      case is_symb_list(Args) of
                          true -> AddFb({V,length(Args)}, Fs, L, St);
                          false -> {Fs,bad_form_error(L, lambda, St)}
                      end;
                  ({V,['match-lambda',[Pats|_]|_],L}, {Fs,St}) ->
                      case is_proper_list(Pats) of
                          true -> AddFb({V,length(Pats)}, Fs, L, St);
                          false -> {Fs,bad_form_error(L, 'match-lambda', St)}
                      end;
                  (_, Acc) -> Acc                 %Error here flagged later
              end,
      foldl(Check, {[],St0}, Fbs0).
  
  %% check_if(IfBody, Env, Line, State) -> State.
  