anchor.diff:  assert(Fun,Tag) ->
     try Fun()
     catch 
  -    _:{_,{error,{1,erl_parse,L}}} -> exit({Tag,lists:flatten(L)});
  -    _:R                           -> exit({Tag,R})
  +    _:{_,{error,{1,erl_parse,L}}}-> exit({{syntax_error,lists:flatten(L)},Tag});
  +    _:R                          -> exit({R,Tag})
     end.
   
   
  
positive.code:   try MS=Method(Str),Str
    catch 
      _:{MS,_} -> Str;
      _:{_,MS} -> Str;
      C:R      -> {C,R,Str,erlang:get_stacktrace()}
    end.
  
negative.code:   [ac_fun(A)|| A <- As].
  
  ac_fun("stack") -> {message,{process_dump}};
  ac_fun("return")-> {return_trace};
  ac_fun(X)       -> exit({unknown_action,X}).
  
  compile_guards(Gs,Vars) ->
    {Vars,O} = lists:foldr(fun gd_fun/2,{Vars,[]},Gs),
  