Thanks, I filed this issue at https://bugs.ecmascript.org/show_bug.cgi?id=387
Regards, Yusuke Suzuki On Thu, Jun 14, 2012 at 12:47 AM, Allen Wirfs-Brock <[email protected]>wrote: > could you file this as a bug at bugs.ecmascript.org > > I want to make sure it isn't forgotten if nobody else responds. > > Allen > > > On Jun 11, 2012, at 11:03 PM, Yusuke Suzuki wrote: > > This issue is derived from Esprima issue 81 > http://code.google.com/p/esprima/issues/detail?id=81 > > Hello everyone, > > According to the ECMA262 5.1th, [[Call]] of host object may return > Reference Type. > So, all values using raw [[Call]] result may be Reference Type. > > For example, [[Get]] may return Reference Type if *getter* is a host > object that [[Call]] returns Reference Type. > http://ecma-international.org/ecma-262/5.1/#sec-8.12.3 > As the result, GetValue may return Reference Type because that use result > value of [[Get]] > http://ecma-international.org/ecma-262/5.1/#sec-8.7.1 > > And, for example, if we define getter of object, getter function is host > object that [[Call]] return Reference Type, > > (10, obj.getter) > > returns Reference type, so, > > (10, obj.getter) = 10; > > is valid because GetValue is performed, but GetValue result is also > Reference Type. > > In the ECMA262 5.1th, GetValue is assumed that doesn't return Reference > Type, for exmaple, > > var obj = { > get v() { > // this v function is host object and returns Reference; > // we can define this v using host object and defineProperty > return Reference; > } > }; > > And, > > typeof obj.v > > Then, typeof should treat Reference Type also, but in 11.4.3, Reference > Type is not considered. > http://ecma-international.org/ecma-262/5.1/#sec-11.4.3 > > I think this is a bug of spec and GetValue and [[Get]] should not return > Reference type, is it right? > > To fix this, I think following 3 way are good. > > 1. perform GetValue on [[Call]] result in the spec > 2. re-define [[Get]] and GetValue can return Reference Type. This > needs to re-define all the spec part using [[Get]], GetValue and others > 3. remove feature that [[Call]] can return Reference Type > > Because all modern engines don't consider that [[Call]] result is > Reference and this feature makes big performance-regression, personally I > think 3 is better. > > Regards, > Yusuke Suzuki > _______________________________________________ > es-discuss mailing list > [email protected] > https://mail.mozilla.org/listinfo/es-discuss > > >
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