[Phillip J. Eby]
... As Tim suggested, it'd be better to have the code be generator-specific, at least for now. That had actually been my original plan, to make it generator-specific, but I was afraid of breaking encapsulation in the garbage collector by having it know about generators.
It sucks in a way, but so would adding yet another new slot just for (at present, and possibly forever) making gc and generators play nicer together. "Practicality beats purity" here.
But now that Uncle Timmy has blessed the approach, I'll go back and add it in. (On Monday, unless somebody gets to it before me.)
It won't be me: I wasn't even able to make enough time to understand the new generator features at the Python level, let alone the implementation. At PyCon, when Guido showed his slide with a new yield-as-expression example, for the rest of his talk I was wondering what the heck the example meant <0.3 wink>.