anchor.diff:  id(T) -> T.
   
   %% terms/0
  -%%
  -%% Return: list of {Term, [Pid, ...]}
  +
  +-spec terms()
  +   -> [{term(), [pid()]}].
   
   terms() ->
       to_list(fun id/1).
  
positive.code:     call(uptime).
  
  %% pids/0
  %%
  %% Return: list of {Pid, [Term, ...]}
  
  pids() ->
      to_list(fun swap/1).
  
negative.code: %% It's up to the caller to ensure that the wait won't be forever.
  %% ===========================================================================
  
  -spec wait(any())
     -> [{term(), pid()}].
  
  wait(Pat) ->
      call({wait, Pat}).
  
  