[Python-Dev] Backwards compatiblity

[Raymond Hettinger]

For 2.2.2, if we add False,True=0,1 to __builtins__, then code written for 2.3 will more likely run without modification.  For
instance, that is all the sets module need to run under 2.2.

Since 2.2 may end-up being the Py-in-a-Tie and because we want 2.3 book examples to be likely to run in an older environment, I
propose we add the two builtins.  Further, since we don't want to encourage further propagation of custom dictionary based sets,
we should consider adding the sets module also.  In both cases, it can't hurt to add the extra functions and it can certainly help
some of the time.


Raymond Hettinger