[Python-Dev] Speeding up name lookups (original) (raw)

Oren Tirosh oren-py-d@hishome.net
Wed, 21 Nov 2001 11:24:15 -0500

On Wed, Nov 21, 2001 at 04:01:04PM +0100, M.-A. Lemburg wrote:

Oren Tirosh wrote: > > [Define name type for lookup purposes]

Just as note: Guido once proposed to cache (almost) all results of global lookups in the frame object. This causes some incompatibilities for e.g. global symbols that change their value after the first lookup.

My idea is different because cache coherence is guaranteed. The item cached inside the name object is a shortcut "cookie" into the entry of the real dictionary and its validity can be verified with just a few instructions.

I'm not sure whether your approach goes in the same direction, but I think that we might be better off using some form of descriptor for this than using a new type.

The thing I like about using name objects is that is touches so few places in the code. Any other approach I have tried resulted in chasing down lots of places where cache coherency might be broken and, serious changes to the bytecode, compiler etc.

I'd suggest to write this up as a PEP.

The idea is still evolving too fast, soon.

Oren