Concurrency support?

Brendan Eich brendan at
Mon Jun 26 13:50:49 PDT 2006

On Jun 26, 2006, at 1:49 PM, Graydon Hoare wrote:

> [Accurate summary of Python trampoline scheduler]

> So, follow-on question: what's *wrong* with the lua strategy?  
> Moreover, why did the python strategy turn out this way? Did the  
> python group just not understand the better strategy? Were they  
> concerned about the restriction of being unable to yield through C  
> stack frames?

Yes, and that is a concern for us, for Rhino's Continuation object  
implementation (which cannot cross Java native frames), as for  
Python.  Several TG1 members have expressed concern about having to  
save and restore even N > 1 interpreted frames, IIRC.  Adobe and  
Opera folks, please comment.

> That seems unlikely since the same restriction probably applies to  
> PEP 324 yields.

No, it doesn't.  There is no yield across more than one level of call.

> Maybe they were bound by semi-compatibility with the existing (and  
> even weaker) iterator/generator scheme in earlier python versions?

I don't think so, but I'd have to ask around to be sure.


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