I've been through the thread and I haven't read any use case that
*requires* Weak References. Only use cases where they make life easier to
various degrees. It's been agreed that in most cases, adding an explicit
.dispose() or equivalent protocol could work too.
Very few things added to ES6 is
On Wed, Apr 3, 2013 at 2:13 AM, Marius Gundersen gunder...@gmail.comwrote:
I've been through the thread and I haven't read any use case that
*requires* Weak References. Only use cases where they make life easier to
various degrees. It's been agreed that in most cases, adding an explicit
Le 03/04/2013 11:13, Marius Gundersen a écrit :
A core part of the problem here is that the distinction between an
'important' reference - one that must keep an object alive - and an
'incidental' reference, that only need exist as long as it target does...
This is a concept which cannot be
On Wed, Apr 3, 2013 at 11:20 AM, David Bruant bruan...@gmail.com wrote:
Le 03/04/2013 11:13, Marius Gundersen a écrit :
A core part of the problem here is that the distinction between an
'important' reference - one that must keep an object alive - and an
'incidental' reference, that only
Le 03/04/2013 21:18, Mark S. Miller a écrit :
Do languages which added WeakRefs have a form of revokable
reference too? What difference would it make?
E has both. In practice, my sense is that their use cases are
disjoint, and that both are needed.
Do you have examples of use? May
On Wed, Apr 3, 2013 at 1:10 PM, David Bruant bruan...@gmail.com wrote:
Le 03/04/2013 21:18, Mark S. Miller a écrit :
Do languages which added WeakRefs have a form of revokable reference
too? What difference would it make?
E has both. In practice, my sense is that their use cases are
On 4/1/13 at 5:40 AM, sa...@ccs.neu.edu (Sam Tobin-Hochstadt) wrote:
Using `.dispose()` is manual management of the allocation and
deallocation of object. Manual memory management is fundamentally
non-modular -- you can't encapsulate it in a library, and it requires
describing memory management
An important distinction here - and one I think Bill and Brendan and others
have gotten at some, and I've been trying to get at - is that weak
references (and similar concepts, like weak maps and weak event listeners)
unfortunately encompass a set of different problems and end up being used
to
Le 27/03/2013 00:22, Kevin Gadd a écrit :
OK, it seems like Weak References are now being discussed without the
context of previous discussions of weak references, which is a little
annoying. Non-contrived real-world use cases that require Weak
References (or a primitive with similar
On Mon, Apr 1, 2013 at 8:34 AM, David Bruant bruan...@gmail.com wrote:
Le 27/03/2013 00:22, Kevin Gadd a écrit :
OK, it seems like Weak References are now being discussed without the
context of previous discussions of weak references, which is a little
annoying. Non-contrived real-world use
Right.
David, I thought I had you convinced at:
http://www.mail-archive.com/es-discuss@mozilla.org/msg21480.html
/be
Sam Tobin-Hochstadt wrote:
On Mon, Apr 1, 2013 at 8:34 AM, David Bruantbruan...@gmail.com wrote:
Le 27/03/2013 00:22, Kevin Gadd a écrit :
OK, it seems like Weak
Le 27/03/2013 00:22, Allen Wirfs-Brock a écrit :
On Mar 26, 2013, at 2:57 PM, David Bruant wrote:
Le 26/03/2013 21:12, Allen Wirfs-Brock a écrit :
On Mar 26, 2013, at 12:18 PM, Mark S. Miller wrote:
WeakSet may or may not happen by ES6. But even if it doesn't,
WeakSet is trivially shimmable
Please read the memory safety and weak references thread.
The issue is not just SES, which might remove an iterator in preparing
the environment. Stock JS must not be vulnerable to jit-spray attacks
due to enumerable weak maps.
/be
David Bruant wrote:
I agree, but I don't see how it
On Tue, Mar 26, 2013 at 3:05 PM, Brendan Eich bren...@mozilla.com wrote:
Hi Jason, agree on your request for non-contrived use-cases. I wrote about
the general observer pub/sub problem here:
http://www.mail-archive.com/es-discuss@mozilla.org/msg21480.html
Hope it helps.
M. It does.
Le 27/03/2013 15:52, Brendan Eich a écrit :
Please read the memory safety and weak references thread.
The issue is not just SES, which might remove an iterator in preparing
the environment. Stock JS must not be vulnerable to jit-spray attacks
due to enumerable weak maps.
From what I
David Bruant wrote:
Le 27/03/2013 15:52, Brendan Eich a écrit :
Please read the memory safety and weak references thread.
The issue is not just SES, which might remove an iterator in
preparing the environment. Stock JS must not be vulnerable to
jit-spray attacks due to enumerable weak maps.
On Mar 27, 2013 6:40 PM, Brendan Eich bren...@mozilla.com wrote:
David Bruant wrote:
Le 27/03/2013 15:52, Brendan Eich a écrit :
Please read the memory safety and weak references thread.
The issue is not just SES, which might remove an iterator in preparing
the environment. Stock JS must
Sam Tobin-Hochstadt wrote:
Changing the disagreement to be about JS vs. its impls is off the
mark. Can you re-defend enumerability of weakmaps now that I've
pointed out the security risk does not apply only to SES users, to be
addressed by SES removing the @iterator?
I don't think this is
On Wed, Mar 27, 2013 at 9:09 PM, Brendan Eich bren...@mozilla.com wrote:
What Dion's attack shows is that conservative stack scanning, when
combined with any ability to observe GC, will leak some information about
the addresses of objects. This can almost certainly be generalized to any
Sam Tobin-Hochstadt wrote:
However, I think this demonstration makes a much stronger case against
conservative GC. Dion's attack requires, fundamentally, three things:
1. Conservative GC (of any form).
2. Some data structure that the browser holds weakly if at all, but
can be held strongly
So to summarize:
- This would be very useful in large MVC applications with many independent
components.
- Even with WeakMaps there is no way to implement weak event listeners,
since WeakMaps cannot be iterated. A weak reference implementation would
solve this.
- The main problem with weak event
2013/3/25 Erik Arvidsson erik.arvids...@gmail.com
WeakMap would not work in this specific case since a WeakMap cannot be
iteratered.
I thought there was an iterable WeakSet for ES6. Was it postponed to ES7 or
just dropped?
Thanks,
Juan
___
2013/3/26 Juan Ignacio Dopazo dopazo.j...@gmail.com
2013/3/25 Erik Arvidsson erik.arvids...@gmail.com
WeakMap would not work in this specific case since a WeakMap cannot be
iteratered.
I thought there was an iterable WeakSet for ES6. Was it postponed to ES7
or just dropped?
I doubt
On Tue, Mar 26, 2013 at 9:46 AM, Tom Van Cutsem tomvc...@gmail.com wrote:
2013/3/26 Juan Ignacio Dopazo dopazo.j...@gmail.com
2013/3/25 Erik Arvidsson erik.arvids...@gmail.com
WeakMap would not work in this specific case since a WeakMap cannot be
iteratered.
I thought there was an
From: Rick Waldron [waldron.r...@gmail.com]
TC39 reached consensus on the inclusion of WeakSet, though it needs to be
designed:
https://github.com/rwldrn/tc39-notes/blob/master/es6/2012-09/sept-19.md#weakset
Is this ES6 timeframe, or ES7? I have run into a few use cases for it since
hearing
On Tue, Mar 26, 2013 at 12:23 PM, Domenic Denicola
dome...@domenicdenicola.com wrote:
From: Rick Waldron [waldron.r...@gmail.com]
TC39 reached consensus on the inclusion of WeakSet, though it needs to
be designed:
On Tue, Mar 26, 2013 at 12:28 PM, Rick Waldron waldron.r...@gmail.com wrote:
On Tue, Mar 26, 2013 at 12:23 PM, Domenic Denicola
dome...@domenicdenicola.com wrote:
From: Rick Waldron [waldron.r...@gmail.com]
TC39 reached consensus on the inclusion of WeakSet, though it needs to
be
WeakSet may or may not happen by ES6. But even if it doesn't, WeakSet is
trivially shimmable on WeakMap.
WeakRef will definitely not happen earlier than ES7. I do hope it will
happen in ES7, but this discussion has yet to happen.
On Tue, Mar 26, 2013 at 4:30 PM, Sam Tobin-Hochstadt
On Mon, Mar 25, 2013 at 9:29 PM, Erik Arvidsson
erik.arvids...@gmail.com wrote:
WeakMap would not work in this specific case since a WeakMap cannot be
iteratered.
What would work here is determinism:
https://gist.github.com/jorendorff/5245857
For this, a deterministic API is just as easy to
Hi Jason, agree on your request for non-contrived use-cases. I wrote
about the general observer pub/sub problem here:
http://www.mail-archive.com/es-discuss@mozilla.org/msg21480.html
Hope it helps. One specific thought below.
Jason Orendorff wrote:
What would work here is determinism:
On Mar 26, 2013, at 12:18 PM, Mark S. Miller wrote:
WeakSet may or may not happen by ES6. But even if it doesn't, WeakSet is
trivially shimmable on WeakMap.
Which is why it isn't the in the spec. yet. It was introduced in support of
Proxy private Symbol white list, but it is still unclear
On 3/26/2013 1:03 PM, David Bruant wrote:
I'm starting to wonder whether bringing weakrefs is equivalent to
having iterable WeakMaps... And if so, why not make WeakMaps iterable?
This is a question I had as well. An iterable WeakMap is nearly the same
as a Map full of WeakRefs, is it not? Just
Le 26/03/2013 21:26, Brandon Benvie a écrit :
On 3/26/2013 1:03 PM, David Bruant wrote:
I'm starting to wonder whether bringing weakrefs is equivalent to
having iterable WeakMaps... And if so, why not make WeakMaps iterable?
This is a question I had as well. An iterable WeakMap is nearly the
Le 26/03/2013 21:12, Allen Wirfs-Brock a écrit :
On Mar 26, 2013, at 12:18 PM, Mark S. Miller wrote:
WeakSet may or may not happen by ES6. But even if it doesn't, WeakSet
is trivially shimmable on WeakMap.
Set is also shimmable on top of Map. If Set is in, there are as many
reason to have
Le 26/03/2013 22:56, Mark S. Miller a écrit :
Because the weak-map-maker constructor grants no privilege and can be
generally accessible, whereas the weak-ref-maker grants the privilege
of being able to observe the non-determinism of GC, and so should not
be made accessible to code that
On Tue, Mar 26, 2013 at 10:14 PM, David Bruant bruan...@gmail.com wrote:
Le 26/03/2013 22:56, Mark S. Miller a écrit :
Because the weak-map-maker constructor grants no privilege and can be
generally accessible, whereas the weak-ref-maker grants the privilege of
being able to observe the
On Mar 26, 2013, at 2:57 PM, David Bruant wrote:
Le 26/03/2013 21:12, Allen Wirfs-Brock a écrit :
On Mar 26, 2013, at 12:18 PM, Mark S. Miller wrote:
WeakSet may or may not happen by ES6. But even if it doesn't, WeakSet is
trivially shimmable on WeakMap.
Set is also shimmable on top of
OK, it seems like Weak References are now being discussed without the
context of previous discussions of weak references, which is a little
annoying. Non-contrived real-world use cases that require Weak References
(or a primitive with similar capabilities, like a Map with weak values
instead of
On Tue, Mar 26, 2013 at 11:22 PM, Kevin Gadd kevin.g...@gmail.com wrote:
OK, it seems like Weak References are now being discussed without the
context of previous discussions of weak references, which is a little
annoying. Non-contrived real-world use cases that require Weak References
(or a
I tried posting this before, but it seems to have gotten lost on the
internet.
One thing which is impossible to make in JavaScript today is a weakly
referenced event listener system. In such a system an event listener is not
strongly referenced by the event system, so events are only dispatched
Most use cases I've personally seen for weak events would be satisfied by a
WeakMap of weak event target - event handler. Having the event handler
itself be weak instead of the event target seems strange to me; it
introduces a bunch of nondeterministic behavior that isn't desirable -
sometimes
WeakMap would not work in this specific case since a WeakMap cannot be
iteratered.
WeakRefs are needed to do data binding and pub sub systems like these.
WeakRefs are very likely to be part of ES7. We haven't really talked much
about them formally but informally TC39 members seems to agree.
On Mon, Mar 25, 2013 at 2:55 AM, Marius Gundersen gunder...@gmail.com wrote:
One thing which is impossible to make in JavaScript today is a weakly
referenced event listener system. In such a system an event listener is not
strongly referenced by the event system, so events are only dispatched
Very true, I'm wondering if based on usage today it could make sense to have
this as default behavior on current API?
Benoit
On Mar 25, 2013, at 19:51, Peter Michaux petermich...@gmail.com wrote:
On Mon, Mar 25, 2013 at 2:55 AM, Marius Gundersen gunder...@gmail.com wrote:
One thing which
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