WebIDL attribute reflection

Brendan Eich brendan at mozilla.com
Fri Dec 28 12:24:05 PST 2012

Boris Zbarsky wrote:
> All that said, I feel like I'm missing context in this discussion. Why 
> do we need to change anything about how WebIDL attributes are 
> reflected?  There were good reasons for the current setup, including 
> the fact that it's somewhat widely deployed already (e.g. implemented 
> in Trident and Gecko) and that it allows authors to usefully interpose 
> DOM getters/setters like they can already interpose methods.

David was questioning the new status quo, which is fine -- we benefit 
from being skeptical of our theories, as Feynman recommended. He was 
motivated by the extra complexity of ES5 accessors, which can be 
reflected on, extracted as get and set functions, called on wrong objects.

Your reply helps a lot, IMHO, in reaffirming why WebIDL, with Gecko, and 
Trident implementing, chose prototype-homed accessors. JITting 
proto-accessors is a thing engines already do. JITting through proxy 
traps (ignoring dummy target overhead) is in the future.

(And let's not ignore the dummy target overhead!)

David, are you convinced?


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