Including Tom because proxies and MOP.
/be
Erik Arvidsson wrote:
This was never resolved and the spec is incomplete here
On Wed Sep 25 2013 at 6:17:32 PM, Allen Wirfs-Brock
<al...@wirfs-brock.com <mailto:al...@wirfs-brock.com>> wrote:
So here is another concern, about the scheme we agreed to last week.
It needs to match a found own property against the possibility of
an own @@unscopable property on the same object and that object
may be somewhere up the inheritance chain of the actual with
object. The means that [[HasProperty]]/[[Get]]/[[Set]] can not be
used to do those resolve binding in an ObjectEnvironmentRecord
because they don't tell us where the property was found. Instead,
ObjectEnvironmentRecord needs to reimplement its own property
lookup using [[GetOwnProperty]] and [[GetInheritanceOf]].
However, if the with object is a proxy that means we may be
bypassing the actual inheritance mechanism implemented by the
Proxy's 'has'/'get'/'set' traps and that could introduce
observable semantics irregularities.
Specifying the duplicated lookup is doable but a pain. That and
the semantic issues WRT proxies makes me a lot less comfortable
with the added complexity of supporting @@unscopable.
Allen
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