Will any new features be tied to constructors?

Boris Zbarsky bzbarsky at mit.edu
Thu Jul 2 04:26:17 UTC 2015

On 7/2/15 12:18 AM, Kevin Smith wrote:
>     I actually do have a related question, though.  In the private state
>     proposals we're talking about, how would it be observable whether the
>     private slots the class defines are in fact allocated as part of the
>     object's allocation or separately?
> Not sure I understand the question.  If the internal shape is fixed from
> birth (allocation-time), there is no way to allocate private slots
> separately.

Ah, I see.  So what's observable is not whether things are a contiguous 
chunk of memory or whatnot but rather whether the slots exist.  And a 
proposed invariant is that the slots, once observed to exist or not 
cannot change that state.  Is my understanding correct now?

> Are you suggesting that the DOM could define some magic way to
> dynamically allocate private slots and supposedly hide that fact from
> the user?

Not suggesting anything yet; just trying to understand the constraints 
we have here.

As a matter of implementation, it would probably be possible to 
implement private slots in the spec sense in a way that can be 
dynamically added to existing objects.  But that's not the externally 
visible behavior being proposed for private slots, which makes sense.


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