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Re: Can't implement §4.6.4 [[DefineOwnProperty]] with Proxies

From: Cameron McCormack <cam@mcc.id.au>
Date: Sat, 18 Jun 2011 17:29:56 +1200
To: David Flanagan <dflanagan@mozilla.com>
Cc: public-script-coord@w3.org
Message-ID: <20110618052956.GB30408@wok.mcc.id.au>
David Flanagan:
> I really like the new §4.6 on indexed properties.  Thanks, Cameron!


> Note, however, that the proxy handler defineProperty() trap is not
> passed the Throw parameter that is passed to [[DefineOwnProperty]],
> so a proxy-based implementation of §4.6.4 is problematic since it
> can't know whether to throw a TypeError or not.

Ah, I didn’t realise that.

> This may be a Proxy bug rather than a WebIDL bug, however.  I
> brought it up on es-discuss last month, but there wasn't really any
> resolution.  The most interesting message in that thread is here:
> https://mail.mozilla.org/pipermail/es-discuss/2011-May/014728.html.
> I'll try to follow up on that.

It seems like proxies should allow throwing/ignoring based on strict
modeness of the caller.  I’ll leave the requirements to Reject in there
for now.

Cameron McCormack ≝ http://mcc.id.au/
Received on Saturday, 18 June 2011 05:30:29 UTC

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