User model stacking: current status

[Dan Smith]

> On May 9, 2022, at 10:10 AM, Kevin Bourrillion <kevinb at google.com> wrote:
> 
>>> But seriously, we won't get away with pretending there are just 3 buckets if we do this. Let's be honest and call it B4.
>> "Bucket" is a term that makes sense in language design, but need not flow into the user model.  But yes, there really are three things that the user needs control over: identity, zero-friendliness, atomicity.  If you want to call that four buckets, I won't argue.
>> 
> I *am* of course only caring about the user model, and that's where I'm saying we would not get away with pretending this isn't a 4th kind of concrete class.

Here's a presentation that doesn't feel to me like it's describing a menu with four choices:

In Java, there are object references and there are primitives. For which kinds of values are you trying to declare a class?

If object references: okay, do your objects need identity or not?

If primitives: okay, do your primitives need atomicity or not?