anchor.diff:  %% -compile([export_all]).
   
   -import(lfe_env, [new/0,add_fbinding/4,is_fbound/3,
  -                  add_mbinding/3,is_mbound/2,get_mbinding/2]).
  +                  add_mbinding/3,is_mbound/2,get_mbinding/2,
  +		  add_vbinding/3]).
   
   -import(lfe_lib, [is_symb_list/1,is_proper_list/1]).
   
  
positive.code:     {Pfs1,Env1,St1} = pass_forms(Pfs0, Env0, St0),
      {['progn'|Pfs1],Env1,St1};
  pass_form(['eval-when-compile'|Ewcs0], Env0, St0) ->
      {Ecws1,Env1,St1} = pass_ewc(Ewcs0, Env0, St0),
      {['progn'|Ecws1],Env1,St1};
  pass_form(['define-macro'|Def]=F, Env0, St0) ->
      case pass_define_macro(Def, Env0, St0) of
          {yes,Env1,St1} ->
              {['progn'],Env1,St1};               %Must return a valid form
          {no,St1} ->
              %% Ignore it and pass it on to generate error later.
              {F,Env0,St1}
      end;
  pass_form(F, Env, St0) ->
      %% First expand enough to test top form, if so process again.
  
negative.code: pass_expand_expr(E, _, St, _) -> {no,E,St}.
  
  %% pass_define_macro([Name,Def], Line, Env, State) ->
  %%     {yes,Env,State} | no.
  %%  Add the macro definition to the environment. We do a small format
  %%  check.
  
  