On Sep 11, 2014, at 1:37 PM, Jason Orendorff wrote: > It seems like new^ is a new argument that is implicitly passed to all > functions. > > What does new^ mean in an arrow function? > > How does new^ interact with a proxy whose target is a constructor? >
see https://github.com/rwaldron/tc39-notes/blob/master/es6/2014-07/instantiation-reform.pdf `new^` has the value of the receiver argument to the [[Construct[[ internal method. This is a parameter newly added to [[Construct]]. Normally it is set to the the value that `new` is applied to. But for `new super` calls it is set to the current `new^` value. In that regard it is like the "receiver" parameter to [[Get]] and [[Set]]. If a constructor is invoked via [[Call]] `new^` has the value `undefined`. that's how you can test for "called as a function" vs. "called as a constructor". `new^` is lexically scoped, just this `this` and `super`. If an arrow function references `new^` it is the value of the closest lexically enclosing constructor function (a function that implements [[Construct]]). Just like [[Get]] and [[Set]], the trap for [[Construct]] is extended to include a "receiver" parameter. Allen > -j > > > On Thu, Sep 11, 2014 at 3:00 PM, Allen Wirfs-Brock > <[email protected]> wrote: >> oh oops! they are supposed to be "new^". Will fix... >> >> On Sep 11, 2014, at 12:55 PM, Boris Zbarsky wrote: >> >>> On 9/11/14, 12:35 PM, Allen Wirfs-Brock wrote: >>>> https://gist.github.com/allenwb/291035fbf910eab8e9a6 summaries the >>>> main syntactic changes since the meeting and provides rationales them. >>>> These features are common to both alternates. this is a good place to >>>> start, after reading the meeting notes. >>> >>> Allen, thanks for putting this together! >>> >>> I have a question: what do the uses of "this^" in this document mean? Are >>> those meant to be "new^"? >>> >>> -Boris >>> _______________________________________________ >>> es-discuss mailing list >>> [email protected] >>> https://mail.mozilla.org/listinfo/es-discuss >>> >> >> _______________________________________________ >> es-discuss mailing list >> [email protected] >> https://mail.mozilla.org/listinfo/es-discuss >
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