Eliot Miranda wrote:
A *much* better way to implement this is to support immutability in the VM (I know, I know, but all the code is available in the Newspeak VM), mark objects one wants to mark as dirty as immutable, catch the NoModificationError exception, and proceed after having made the object mutable and marked it dirty. No creating hidden classes, no trying to get change class to work for compact classes, etc. Just a simple VM-implemented write barrier that can also be used for a host of other things (object-database mapping, debugging, immutable literals etc).
Since object dirtying is at the core of the product I work with, and I've worked extensively with both methods of implementing write barriers... I very strongly agree with Eliot. *So* much nicer a way to do this. Regards, -Martin