2010/9/2 Leo Meyerovich <lmeye...@gmail.com>: > > On Sep 2, 2010, at 12:29 AM, Brendan Eich wrote: > >> On Sep 2, 2010, at 12:08 AM, Leo Meyerovich wrote: >> >>> That said, going back to the beginning: deterministic GC-independent >>> semantics are a Good Thing. Whether this matters seems to be a crucial >>> discussion. Is there a concern for basic correctness for more mundane code? >>> Are those use cases similar to the above where a 'strictness' library >>> suffices? Again, I'd point to the ActionScript experience for a reference: >>> can anybody attack or break a flash program with weak maps, or is this FUD? >>> I'm more concerned about the dangers of misuse in terms of memory leaks and >>> event-oriented logic glitches between code running on different ES >>> implementations (and suspect the answer has a reasonable chance of being >>> 'yes' for these). >> >> I tend to agree that the answer is 'yes', assuming the question was "Whether >> [deterministic GC-independent semantics] matters" ;-). >> > > > Leaving how in question -- e.g., achievable with a simple library toggle -- > and whether it *always* matters (such as for those would want the enumeration > ability and could arguably contain the non-determinism). > > >> It's hard to make an airtight case for "security" even on a good day, but >> removing observability from the weak maps proposal makes it strictly simpler >> and less likely to cause any number of problems. I don't believe that lack >> of enumerability and .length cripples the API for the intended use cases of >> soft fields, membrane caches, and the like. >> >> /be >> > > There are use cases for enumeration like proper native GC in data flow > abstractions and it seems others that have piped up with their own uses. > Obviously, different people on this list have presented different use cases > for weak maps and it seems those two exact scenarios it. I'd be curious about > further ones for enumeration (which I suspect surface in proper > implementations of various event-oriented abstractions) and weak maps in > general -- it may be we're the only ones who care and only those two > scenarios are important to the committee members ;-) For example, the ability > to trigger a purge might matter for reliability in some uses (which I'd > suspect for certain transient resource pools), even if it's a no-op wrt JS > semantics.
I would strongly oppose any way to trigger a full garbage collection from JavaScript. Experience from the Java world shows that it is inevitably abused with very serious performance consequences. Note the mealy description here with words like "suggests" and "best effort" http://download.oracle.com/javase/1.5.0/docs/api/java/lang/System.html#gc() There is even a command line option on some VMs to disable this call and turn it into a noop. So please no. > > - Leo > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss > _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
