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Re: thread local variables

Per Bothner <bothner@cygnus.com> writes:

> > You have three threads.  Thread a is in a repl.  Threads b and c
> > are cooperating on some task, and want to share a binding for 
> > (current-output-port).  Thread a should have a different binding
> > for (current-output-port).
> 
> Assuming:
> (define (current-output-port) *current-output-port*)
> 
> and that:  (fluid-let ((VAR)) BODY)
> is syntactatic sugar for:  (fluid-let ((VAR VAR)) BODY)
> (I.e. create a new binding but initialize it to the current value);
> 
> you can do:
> 
> (future (fluid-let ((*current-output-port*)) (thread-a)))
> ;; Or: (fluid-let ((*current-output-port*)) (future (thread-a)))
> (fluid-let ((*current-output-port*))
>   (future (thread-a))
>   (future (thread-b)))

Thanks.  You have greatly improved my understanding of what's possible
with fluid-let.  Now I'm going to try to code this up as an actual
example.

-russ

--
In theory, there is no difference between theory and practice. 
But, in practice, there is.