PEP 236: Back to the __future__

[Jeremy Hylton]

>>>>> "KH" == Konrad Hinsen <hinsen at cnrs-orleans.fr> writes:

  KH> Moral: incompatible changes should happen on a time scale
  KH> compatible with uncoordinated collective code development, which
  KH> is years, not months.

The goal of future_statements is to lengthen the time scale for
incompatible changes while allowing some users to access the
functionality now.  With the addition of from __future__ import
nested_scopes, there should be no incompatible changes in 2.1.

At the same time, I expect very little code to require changes to be
compatible with nested scopes.  My own survey of three large projects
found four problems in 200,000 lines of code.  I have yet to hear
statistics for any other project.

Jeremy