Thanks so much, that makes perfect sense.
On 03/16/2011 02:16 PM, Carl Eastlund wrote:
David,
I believe you are seeing the difference between modules and the REPL.
At the REPL, each expression is compiled, run, and discarded. This
yields the behavior you expect. But a "#lang" form produces a module,
which is compiled and kept for the rest of the session. Thus, even
after garbage collection, the compiled form of the first term still
exists:
(define b (make-weak-box 'not-used))
Thus there is a reference to the symbol not-used, and it is not
garbage collected.
Carl Eastlund
On Wed, Mar 16, 2011 at 5:09 PM, David Vanderson
<david.vander...@gmail.com> wrote:
I'm seeing a difference between when the value in a weak box is collected.
When I run the following interactively, the value is collected like I
expect. But it is not collected when running in a script, or in DrRacket.
This is v5.1 on Ubuntu x64, compiled from source.
Can someone explain the difference?
~$ racket
Welcome to Racket v5.1.
(define b (make-weak-box 'not-used))
(weak-box-value b)
'not-used
(collect-garbage)
(weak-box-value b)
#f
~$ cat weak-box.rkt
#lang racket
(define b (make-weak-box 'not-used))
(weak-box-value b)
(collect-garbage)
(weak-box-value b)
~$ racket weak-box.rkt
'not-used
'not-used
Thanks,
Dave
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