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    <div class="moz-cite-prefix">Le 26/11/2012 21:39, David Bruant a
      écrit :<br>
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    <blockquote cite="mid:50B3D37C.9040104@gmail.com" type="cite">
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      <div class="moz-cite-prefix">Le 26/11/2012 20:59, Tom Van Cutsem a
        écrit :<br>
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      <blockquote
cite="mid:CAKDfNj8OeKygd0mZ4j-zBuChfU8Ziu74AoxYvOV_z4WyV08umg@mail.gmail.com"
        type="cite">
        <div class="gmail_quote">2012/11/26 David Bruant <span
            dir="ltr"><<a moz-do-not-send="true"
              href="mailto:bruant.d@gmail.com" target="_blank">bruant.d@gmail.com</a>></span>
          <div><br>
          </div>
          <blockquote class="gmail_quote" style="margin:0 0 0
            .8ex;border-left:1px #ccc solid;padding-left:1ex">We could
            define a symbolic value (like StopIteration for iterators)
            that would mean "forward to target". By essence of what
            forwarding to the target means, there would be no need to
            perform the least invariant check. We can call it
            ForwardToTarget :-)<br>
          </blockquote>
          <div><br>
          </div>
          <div>I think we've previously entertained a similar proposal
            when a handler was encountering the .public property of a
            private property it didn't know, and then wanted to signal
            to the proxy "I don't know this private name, please
            forward".</div>
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      </blockquote>
      True. I had the feeling the idea wasn't entirely knew, but I
      couldn't recall what was the inspiration for it.<br>
      <br>
      <blockquote
cite="mid:CAKDfNj8OeKygd0mZ4j-zBuChfU8Ziu74AoxYvOV_z4WyV08umg@mail.gmail.com"
        type="cite">
        <div class="gmail_quote">
          <div>I recall one issue was that you'd really want a unique
            token per trap invocation, which costs.<br>
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      </blockquote>
      I don't understand why a unique token per trap invocation would be
      necessary.<br>
    </blockquote>
    I still don't understand this point.<br>
    I've gone spelunking. I've found:<br>
    * the wiki page [1] (reflecting July meeting) which mentions that
    returning undefined would express "I don't know the private name,
    please forward"<br>
    * Confirmed on July 31st [2].<br>
    * Introduction of the idea of putting the verification of known
    names somewhere else than for each trap return [3]. Some discussion
    in between about this idea. Introduction of the idea of adding a
    third argument [4] after which I think stops all discussions about
    returning something in traps to prove knowledge of a private name or
    forwarding when not knowing.<br>
    <br>
    I don't remember the point about a token per trap invocation and I
    haven't been able to find it (but I haven't read everything).<br>
    <br>
    In any case, for "throw ForwardToTarget", I don't see why it would
    be necessary. It seems it would work unambiguously with
    meta-handlers, with target-as-a-proxy or with
    manipulate-any-other-proxy-inside-a-trap (which target-as-a-proxy is
    an instance of).<br>
    <br>
    David<br>
    <br>
    [1]
<a class="moz-txt-link-freetext" href="http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies#discussed_during_tc39_july_2012_meeting_microsoft_redmond">http://wiki.ecmascript.org/doku.php?id=harmony:direct_proxies#discussed_during_tc39_july_2012_meeting_microsoft_redmond</a><br>
    [2]
    <a class="moz-txt-link-freetext" href="https://mail.mozilla.org/pipermail/es-discuss/2012-July/024246.html">https://mail.mozilla.org/pipermail/es-discuss/2012-July/024246.html</a><br>
    [3]
    <a class="moz-txt-link-freetext" href="https://mail.mozilla.org/pipermail/es-discuss/2012-July/024256.html">https://mail.mozilla.org/pipermail/es-discuss/2012-July/024256.html</a><br>
    [4]
    <a class="moz-txt-link-freetext" href="https://mail.mozilla.org/pipermail/es-discuss/2012-August/024313.html">https://mail.mozilla.org/pipermail/es-discuss/2012-August/024313.html</a><br>
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