Array.prototype.contains

Brendan Eich brendan at mozilla.org
Sat Nov 3 18:05:02 PDT 2012


Is this true? I can see how enumeration and size would leak the GC 
schedule, but to test has or contains, you need a strong ref, which 
means the key or value cannot yet be garbage. If you have the 
capability, there's no non-determinism. What am I missing?

/be

Allen Wirfs-Brock wrote:
>
> On Nov 3, 2012, at 4:53 PM, Mark S. Miller wrote:
>
>> On Fri, Nov 2, 2012 at 5:26 PM, Allen Wirfs-Brock 
>> <allen at wirfs-brock.com <mailto:allen at wirfs-brock.com>> wrote:
>>
>>
>>     Also any reason contains should be provided for WeakMap? I not
>>     seeing why it shouldn't be there too.
>>
>>
>> Yes!
>>
>> The set of values actually contained by the WeakMap at any moment is 
>> non-deterministic, depending on the scheduling of gc. But this 
>> non-determinism is non-observable. WeakMap.contains would make it 
>> observable.
>
>
> yup
>
>
>
>>
>> -- 
>>     Cheers,
>>     --MarkM
>
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