anchor.diff:  -behaviour(gen_refac).
   
   %% export of callback function.
  --export([input_pars/0, select_focus/1, 
  -         pre_cond_check/1, selective/0,
  +-export([input_par_prompts/0, select_focus/1,
  +         check_pre_cond/1, selective/0,
            transform/1]).
   
  --include("../include/gen_refac.hrl").
  +-include("../include/wrangler.hrl").
   
   %% Ask the user which module to import. 
  --spec (input_pars/0::() -> [string()]).                           
  -input_pars()->
  +-spec (input_par_prompts/0::() -> [string()]).                           
  +input_par_prompts() ->
       ["Module name:"].
   
   %% no focus selection is needed.
  
positive.code:     {ok, none}.
      
  %% Pre-condition checking. 
  -spec (pre_cond_check/1::(#args{}) -> ok | {error, term()}).  
  pre_cond_check(Args=#args{user_inputs=[ModuleName]}) ->
      case collect_uses(Args) of 
          [] ->
              Msg =io_lib:format(
  
negative.code:     end.
  
  selective() ->
      true.
  
  %%Do the actual program transformation here.
  -spec (transform/1::(#args{}) -> 
  