On Nov 22, 2010, at 12:39 PM, Brendan Eich wrote: > On Nov 22, 2010, at 12:09 PM, Oliver Hunt wrote: >> >> How do library authors help? They can't add value enumeration of anything >> as that will break any existing code that uses for(in) over any of their >> objects. > > As Tom pointed out (re-read his message :-|), they can make enumeration work > for large/lazy/infinite objects. No non-string non-keys required.
The important point here is that for-in won't choke old browsers. New library code in the near term (when Harmony and pre-Harmony impls are in the field), assuming we let for-in be metaprogrammed in Harmony, can object-detect and meta-program for-in, and client *and* library code can use for-in and it will fail soft or fall back by other means. Not so if we add new syntax (for-: or anything old browsers will choke on). /be _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
