On Oct 3, 2011, at 8:26 PM, Waldemar Horwat wrote: > On 09/30/2011 08:43 PM, Brendan Eich wrote: >> On Oct 1, 2011, at 5:24 AM, Brendan Eich wrote: >> >>> On Oct 1, 2011, at 4:23 AM, Waldemar Horwat wrote: >>> >>>> There are lots of ways to do classes that satisfy all of 2-5. However, it >>>> doesn't matter if those exist if those solutions are not acceptable to the >>>> group. >>> >>> I know, I was ok with a read barrier for properties to enforce a temporal >>> dead zone for const properties. Others were not ok with whatever overhead >>> that might add to all property reads. >>> >>> But who says we need to solve 5 now? A number of us are saying we can defer >>> it. >> >> And here's how this might then play out: some of us who do value const >> properties prototype them as an extension to minimal classes, and we >> demonstrate in fast VMs that the read barrier cost is negligible. The rest >> of the group is convinced, and we add const properties later (next edition, >> this edition if in time, doesn't matter). >> >> By insisting on solving all of 2-5 up front, when demonstration of >> low-enough cost imposed by implementation of 5 is required by some in the >> group, you guarantee no classes. By letting minimal classes proceed, you >> might get const properties too. >> >> I can't guarantee this, but I can guarantee if we keep going in circles >> we'll have no classes. >> >> You might argue that implementors can prototype solutions for 2-5 already, >> but I think no one will risk it without more consensus in the committee. So >> even if minimal classes is just an agreement for implementors, it would help >> us get to consensus on the solution for 5. Does this make sense? > > Given that the choice seems to be between doing potentially future-hostile > classes (where we'd bemoan the water under the bridge when trying to solve > 2-6) and omitting classes altogether, C.A.R. Hoare's advice (as quoted by > Bill Frantz) to defer classes would be the wiser thing to do. The standard > is not a place for poorly understood features.
I agree. If we had agreed on the read barrier, I think we would probably have consensus on classes. It's interesting that Oliver (Apple) and I (at least, among Mozillans) agreed. Other implementations were not represented in my view. Take this for what it's worth. /be _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
