anchor.diff:  -behaviour(gen_server).
   
   %% API
  --export([start_link/2,
  +-export([start_link/1,
            release/1,
            write/2,
            read/1,
  
positive.code:   {gpio_pin, Pin}.
  
  
  %% @doc value_change(Old, New)
  %% value_change(0, 1) ->
  %%   raising;
  %% value_change(1, 0) ->
  
negative.code: %% value_change(_, _) ->
  %%   no_change.
  
  %%% Local Variables:
  %%% erlang-indent-level: 2
  %%% End:
  