Re: emulating mozilla's Label command

[Chris Green <cmg@dok.org>]

Ted Zlatanov <tzz@lifelogs.com> writes:

> The registry will need reverse mappings to do this, which will use
> memory and CPU.  So it should be optional, and if it's off then it
> will cost the user more CPU to retrieve the reverse mapping (but the
> CPU and memory costs will be localized instead of distributed).
> There should be four settings for caching:
>
> t (build cache ASAP and keep it)
> nil (never, only build cache when needed and release it afterwards)
> 'opportunistic (cache is built when needed and reused later)
> '(...) (list of types of extra data that should be cached, all others
> are built when needed)

Ahh that would be a nice generic feature. I was sitting here thinking
of "oh it wouldn't be hard to copy the hash table stuff to make a
reverse map for labels"..

I'm not sure what nil means here.  The purpose of that variable is to
keep memory down at the potential expense of CPU.  In that mode, a
each cache-reverse lookup would have to do an O(N) search.

Put another way:

Is the difference between 'opportunistic and nil:

  1) saving to disk or
  2) creation of an in-memory cache at all

> What do you think?

Seems like a great solution to me.  
-- 
Chris Green <cmg@dok.org>
To err is human, to moo bovine.