stéphane ducasse wrote:

> Hi
>
> I wanted to know how this was relating to the way VW treats blocks:  
> clean block [:each | each zork], copy blocks and full blocks.
> Does anybody able to compare?

These are different things. The optimized blocks in VW still require 
full context activations, they just avoid issues with references to 
their creating context:
A clean block is completely independent of its context, so VW creates 
the block at compile time and stores it in the literal frame of the method.
A copying block needs some values from the context which are known not 
to be changeable after the block has been created (method receiver and 
arguments and variables which are never assigned to after the block's 
creation), so these values can be copied into the newly created block, 
but the block does not need a reference to its creating context, so that 
context does not have to be stabilized when the method returns.
A full block needs a reference to its context, either because it 
contains a return or because it reads variables which may change after 
its creation, or writes into temporaries outside of its own scope.

In contrast, Dan's scheme does not deal with blocks but activations in 
general, and it tries to avoid creating a stack frame if possible. IMO 
it is an optimization that should be investigated.

Cheers,
Hans-Martin