On Thu, Dec 16, 2010 at 3:51 PM, David Herman <[email protected]> wrote:
> Without new syntax, isn't soft fields just a library on top of weak maps? > Semantically, yes. However, as a library, they cannot benefit from the extraordinary efforts of all JavaScript engines to optimize inherited property lookup. Nor from the GC benefits that follow from the transposed representation explained at < http://wiki.ecmascript.org/doku.php?id=strawman:inherited_explicit_soft_fields#a_transposed_representation>. OTOH, if soft fields are built in and implemented in this transposed manner, both benefits easily follow. > > Dave > > On Dec 16, 2010, at 3:47 PM, Mark S. Miller wrote: > > > > On Thu, Dec 16, 2010 at 3:23 PM, Brendan Eich <[email protected]> wrote: > >> On Dec 16, 2010, at 2:19 PM, Mark S. Miller wrote: >> >> > Currently is JS, x['foo'] and x.foo are precisely identical in all >> contexts. This regularity helps understandability. The terseness difference >> above is not an adequate reason to sacrifice it. >> >> Aren't you proposing the same syntax x[i] where i is a soft field map, to >> make exactly the same sacrifice? >> >> http://wiki.ecmascript.org/doku.php?id=strawman:names_vs_soft_fields > > > I am **not** proposing these syntactic extensions. Neither am I avoiding > them on that page, since the point of that page is to compare semantics, not > syntax. The first paragraph (!) of that page clearly states: > > "This translation does not imply endorsement of all elements of the names > proposal as translated to soft fields, such as the proposed syntactic > extensions." > > > The two issues are orthogonal. Whichever of Names or Soft Fields wins, we > can have an orthogonal argument about whether the winner should use this > syntactic shorthand. Conversely, whatever the outcome of the syntax argument > in this thread, they would apply equally well to either semantics. > > >> >> >> /be >> >> > > > -- > Cheers, > --MarkM > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > > -- Cheers, --MarkM
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