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Re: All ECMAScript attributes should be non-configurable

From: Brendan Eich <brendan@mozilla.org>
Date: Fri, 23 Sep 2011 19:37:23 -0700
Cc: public-script-coord@w3.org
Message-Id: <A292856F-501A-4714-BD33-E9D2F59ABBE7@mozilla.org>
To: David Bruant <david.bruant@labri.fr>
On Sep 23, 2011, at 6:42 PM, David Bruant wrote:

>> No. For "own" the object itself must have a "property map" or equivalent.
> For "inherited", each property must have an internal object-to-value map
> or equivalent.

No, prototype object has that map. You don't need to replicate it in all N=1e6 instances delegating to the prototype. The only thing the instances need (for data properties) are value storage slots.

> Not if the property map is lazily created.

Let's not match implementation c.v.s here. Any lazy approach requires extra state *and* code, to go from lazy to eager. The state, however encoded, must be able to distinguish lazy/unreified from eager/reified. This costs.

Received on Saturday, 24 September 2011 02:37:53 UTC

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