Symbols, Protocols, Frames, and Versioning

Brendan Eich brendan at
Sat Oct 6 14:51:38 PDT 2012

Allen Wirfs-Brock wrote:
> On Oct 6, 2012, at 9:37 AM, Brendan Eich wrote:
>> Domenic Denicola wrote:
>>> I still would like to see someone respond to jjb’s message though:
>> JJB is right about same-origin allowing sharing so making postMessage unnecessary, but same-origin does not mean a symbol created by a module loaded in one frame is the same as the symbol created by that module loaded in a related same-origin frame. That's the trouble.
> Except that symbol creation isn't the issue.  By definition, each time a symbol is "created" you are getting a new unique symbol.  Frames/contexts/realms have nothing to to with that.

I agree, but symbols are the nominal issue in this thread.

> The issue, is providing access to an already created symbol across such boundaries.  As I have pointed out in other messages, this isn't a problem that it unique to symbols.  It is isomorphic with use cases for sharing any kind of object across such boundaries.

Indeed, as Tom said just 15 messages up-thread:

''If symbols break across frames, I think the fault lies not with the 
symbols. I think the fault lies with the fact that the object on which 
the symbol was defined didn't "properly" cross the frame boundaries. 
Perhaps we need better abstractions to interpose between frame boundaries?''


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