If you mean it should be a module

I think he meant you were proposing a solution that would feature faster performance at the expense of added complexity in both the code and the data structure. Programmers who think in Perl tend not to think that way unless performance becomes a user-noticeable problem (and sometimes not even then -- depending on the situation, we sometimes prefer to throw hardware at performance issues until they go away, rather than make code maintenance harder; obviously sometimes that isn't a good option; O(n!) for example will eat any amount of hardware and ask when the soup course is coming).