Re: sqlite3

[Tomas Hlavaty]

On Sat 18 Dec 2021 at 09:06, Qiantan Hong <qhong@mit.edu> wrote:
> The feature of hash-consing is exactly not preserving EQness,
> or, under hash-consing EQ and EQUAL degenerate to the same thing
> (Aka, intensional and extensional identity degenerates), effectively
> removing the concept of EQ and object identity from the language all 
> together.

It is the other way round:  hash-consing "reduces" EQUAL to EQ.

It does not remove the concept of identity.

> In layman’s term: even if two objects’ value look the same, they may
> or may not be the same object.
> The difference become apparent when
> you poke one, and the other may or may not change.

That is a consequence of having more than one definitions of same-ness.

> Therefore I conclude that maybe preserving EQness in persistent store
> does not make that much sense (otherwise why it can only be preserved
> partially?).

It could preserve EQness if every object, where EQness has to be
preserved, was also stored under different key.

Or there would have to be a way to reference objects stored inside the
structure saved under different key.  (Some kind of extended syntax for
print-circle labels.)