anchor.diff:                                            end
                                     end, Args0),
                    {M, F, Args}
  -             end || Match <- Matches, hd(Match) =/= <<>>]
  +             end || Match <- Matches]
       end.
   
   %% @doc execute the tasks.
  
positive.code: %% Task Functions
  %%----------------------------------------------------------------------------------------------------------------------
  
  task_remind(Text, Channel) ->
      Matches = matches(Text, <<"https?://[^\\s]*(pull|issue)/[0-9]*">>),
      Urls = [GithubUrl || [GithubUrl | _] <- Matches],
  
negative.code:     do_1(In#{<<"text">> => PreText, <<"attachments">> => nil});
  do_1(#{<<"type">> := <<"message">>, <<"text">> := Text, <<"channel">> := Channel}) ->
      Tasks0 = [
                {{mention, <<"remind.*">>},                           {?MODULE, task_remind,     [Text, Channel]}},
                {<<"https?://[^\\s]*(pull|issue)/[0-9]*">>,           {?MODULE, task_github_url, ['$$']}},
                {{mention, <<"list\\s(.*)">>},                        {?MODULE, task_list,       ['$1', Channel]}},
                {{mention, <<"register\\s+([^\\s]*)\\s+([^\\s]*)">>}, {?MODULE, task_register,   ['$1', '$2', Channel]}},
                {{mention, <<"user\\s+([^\\s]*)">>},                  {?MODULE, task_user,       ['$1', Channel]}},
                {{mention, <<"help.*">>},                             {?MODULE, task_help,       [Channel]}},
                {{mention, <<".*">>},                                 {?MODULE, task_help,       [Channel]}}
               ],
      Tasks = choose_tasks(Text, Tasks0),
      execute_tasks(Tasks);
  