[gclist] Re: gclist-digest V2 #91

[Urs Hoelzle]

> Date: Wed, 10 Dec 1997 09:18:44 -0500
> From: David Chase <chase@world.std.com>
> Subject: Re: [gclist] object identity & copying collection
> 
> I saw what looked like a clever trick on the Squeak mailing list.
> There, each option header has two bits reserved for storing one of
> three states:
> 
>   1. no hash code computed
>   2. hash code is address
>   3. hash code follows object
> 
> The usual case is #1.  When Object.hashCode is requested, the object
> is placed in state #2.  When the object is moved, it is placed in state
> #3.

To give credit where credit is due, I believe this idea is due to Ole
Agesen at SunLabs.  As far as I know this neat trick hasn't been
published yet.

-Urs