Re: sqlite3

[Lars Ingebrigtsen]

Qiantan Hong <qhong@mit.edu> writes:

> They don’t really make sense when storing to 
> external storage, at least for all the mechanisms
> either you or I have. Because our storage mechanism
> doesn’t preserve intensional identity (“object identity”),
> i.e. if two objects are EQ, we store them into different key,
> they might be read back not EQ. We only store extensional
> value. In such case, circular list are no different from
> an infinite non-circular list, which doesn’t make sense.

We don't preserve EQ-ness of objects, but it's still nice to be able to
store a list where the same object appears a number of time (and get out
a list from the storage where that's still true).

> Plus it’s not very common in practice to store circular list
> in something one may want to make persistent. Mostly
> it’s some history variable or so that is push into/delete from,
> neither will make it circular.

We don't use circular lists a lot, but we do have rings, and it's nice
to be able to store them.

I feel that an append-only list storage thing is a totally separate
thing from persistent variables.  There's many different things that
could be taken into consideration when merging elements from different
instances, for instance.  

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no