[Python-Dev] Fast access to __builtins__

[Greg Ewing]

Neil Schemenauer <nas@python.ca>:

> Optimization options that globally change semantics seem like a bad
> idea.  How would you know some module you are using will not break?  I
> agree with Mark that a per-module switch would be better.

There's something a bit strange about this situation,
though.

The compiler knows whether a module shadows any of its
*own* builtins, and can avoid applying the optimisation
to those names. So the optimisation doesn't change the
semantics of the module itself, provided some conditions
are met.

But those conditions depend on things *outside* the
module -- namely, whether any *other* module assigns
to one of this module's globals so as to shadow a
builtin.

This makes me think that having a flag inside the
module is not the right thing to do, or at least it's
not the only thing that's needed. There needs to be
a way to turn the optimisation *off* from outside the 
affected module.

Greg Ewing, Computer Science Dept, +--------------------------------------+
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