[Squeak-e] Programming the VM
Mark S. Miller
markm at caplet.com
Mon Feb 3 01:36:10 CET 2003
At 12:21 AM 2/3/2003 Monday, cg at cdegroot.com wrote:
>Is this looking at Islands, basically, but then nested? Again the $1000
>dollar question arises: by what scope? It seems here that you are
>talking about machines, therefore about execution environment, therefore
>about some form of dynamic scopery.
Let's say object A is instantiated on "machine" X and object B is
instantiated on "machine" Y. Let's say X and Y allow A to call B. The act of
A calling executes on X under X's rules, observation, and control. The
behavior of B being called (executing the called method) likewise executes
on Y. The virtualization/hosting/ownership environment is according to the
object's creation context, not its calling context.
This is lexical scoping, not dynamic scoping, just as Alan's metaphor would
seem to demand. Object references stretch between "machines". Messages move
between "machines" riding references. Objects stay where they're born.
Text by me above is hereby placed in the public domain
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