On Mon, Aug 26, 2013 at 3:02 PM, Allen Wirfs-Brock
<allen at wirfs-brock.com> wrote:
>
> On Aug 26, 2013, at 11:37 AM, Erik Arvidsson wrote:
>
>> I agree that this is crucial. I think that tips the balance over to
>> have to do the Get of @@unscopable on every HasBinding.
>
> How so.  The timing of the @@unscopable property and the the process of using it to filter identifier binding are completely separable procedures. How does restricting the filtering to own properties  change the rationale for  getting the blacklist property once per 'with'  rather than on every variable reference.

I just felt things got a bit too complicated to spec.

I realize now that the complexity is not very different either way.

I'm ambivalent which behavior I prefer. Either way solves the use case
but dynamic lookup has the benefit that will better handle crazy edge
cases like changing @@unscopable and [[Prototype]] within the with
statement.

-- 
erik

I just felt things got a bit too complicated to spec.

I realize now that the complexity is not very different either way.

I'm ambivalent which behavior I prefer. Either way solves the use case
but dynamic lookup has the benefit that will better handle crazy edge
cases like changing @@unscopable and [[Prototype]] within the with
statement.