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.

Dave