anchor.diff:  %% Tested manually.
   -spec get_input() -> {flag | open | unflag, ms_server:pos()} | quit.
   get_input() ->
  -    {ok, Command, Params} = io_lib:fread(
  -                              "~s",
  -                              io:get_line("[u]nflag / [f]lag / [o]pen r c or [q]uit: ")),
  +    {ok, Command, Params} =
  +        io_lib:fread(
  +          "~s",
  +          io:get_line("[u]nflag / [f]lag / [o]pen r c or [q]uit: ")),
       case hd(Command) of
           "f" ->
               get_input_pos(flag, Params);
  
positive.code:     io:format("  f 2 3   flags cell at row 2 column 3 as a mine~n"),
      io:format("  u 2 3   clears flag from cell at row 2 column 3~n"),
      io:format("  o 2 3   opens cell at row 2 column 3~n"),
      io:format("  q       quits the game~n").
  
  
  
negative.code:             get_input_pos(open, Params);
          "u" ->
              get_input_pos(unflag, Params);
          "p" ->
              print;
          "q" ->
              quit;
          _ ->
  