[Python-Dev] violently deprecating exec without in (was: nested scopes. global: have I got it right?)

[Jeremy Hylton]

>>>>> "GvR" == Guido van Rossum <guido@digicool.com> writes:

  >> The nested scopes rules don't kick in until you've got one
  >> function nested in another.  The top-level namespace is treated
  >> differently that other function namespaces.  If a function is
  >> defined at the top-level then all its free variables are globals.
  >> As a result, the old rules still apply.

  GvR> This doesn't make sense.  If the free variables were truely
  GvR> considered globals, the reference to x would raise a NameError,
  GvR> because the exec doesn't define it at the global level -- it
  GvR> defines it at the local level.  So apparently you are
  GvR> generating LOAD_NAME instead of LOAD_GLOBAL for free variables
  GvR> in toplevel functions.  Oh well, this does the job!

Actually, I only generate LOAD_NAME for unoptimized, top-level
function namespaces.  These are exactly the old rules and I avoided
changing them for top-level functions, except when they contained a
nested function.

If we eliminate exec without "in," this is yet another problem that
goes away.

Jeremy