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Re: undefined values in dictionaries

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 18 Jun 2013 08:36:07 -0400
Message-ID: <51C05437.9030301@mit.edu>
To: Cameron McCormack <cam@mcc.id.au>
CC: "Tab Atkins Jr." <jackalmage@gmail.com>, Jonas Sicking <jonas@sicking.cc>, "public-script-coord@w3.org" <public-script-coord@w3.org>
On 6/18/13 3:13 AM, Cameron McCormack wrote:
> I've made the change that treats undefined on an object converted to an
> IDL dictionary as missing:

There are two issues here:

1)  The new text has Type(V) where it means Type(value).
2)  The [[Get]] is happening before we check for whether V is undefined
     or null (this problem was actually preexisting, but with
     [[HasProperty]]).

What Gecko's code for this looks like is more like this (after making a 
change to align with the intent of the spec here):

   If Type(V) is Null or Undefined set value to Undefined.  Otherwise let
     value be the result of calling the [[Get]] internal method on V
     with property name key.
   Let present be false if Type(value) is Undefined and true otherwise.

-Boris
Received on Tuesday, 18 June 2013 12:36:38 UTC

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