Re: sqlite3

[Qiantan Hong]

> but I didn't quite see how that would work with circular and
> self-referential lists.)
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.

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.