On Sun, Jan 12, 2014 at 11:07:19AM -0500, David T. Lewis wrote:
> On Sun, Jan 12, 2014 at 10:50:03AM -0500, Colin Putney wrote:
> > That diff is a bit hard to read, so here's the implementation:
> > 
> > 
> > allObjectsDo: aBlock
> > "Evaluate the argument, aBlock, for each object in the system
> > excluding SmallIntegers. New objects created by aBlock will
> > be included in the enumeration, and it is up to the caller to avoid
> > creating new objects faster than they are enumerated. It's
> > important that the next object is fetched before the block is
> > evaluated, because the block may use #become: to change the
> > identity of object."
> > 
> > | object nextObject |
> > object := self someObject.
> > [nextObject := object nextObject.
> > aBlock value: object.
> > object := nextObject.
> > 0 == nextObject]
> > whileFalse.
> > 
> > 
> > This version has the following properties:
> > 
> > - objects created inside the block will be enumerated
> > - callers may use become inside the block
> > - callers must avoid infinite loop
> > 
> > I think these are the most desirable semantics for #allObjectsDo:. However,
> > the risk with this implementation is that it will execute an infinite loop
> > on VMs that create a new context object for each block activation. Cog and
> > the StackVM don't, but John's Mac VM 5.7.4.1 does, according to a quick
> > test I just did. I don't know what the behaviour of older Window and Linux
> > VMs are.
> > 
> > So  the question is, what VMs are we planning to support for in 4.5, and do
> > they recycle activation contexts?
> > 
> 
> Certainly the up to date interpreter VM and Cog/StackInterpreter will be
> used, but I think that there are some folks who still need to use John's
> Mac VM, so it would be good if we could find a solution that works there
> also.
> 
> But I also like your implementation here, it's simple and easy to understand.

Oops, I should have checked before replying. This implementation does not
seem to work on any standard interpreter VM, so definitely not a good thing.

Dave