(You sent this as private?) On Dec 19, 2015 7:09 PM, "Victor Stinner" <victor.stinner@gmail.com> wrote:

Le 19 déc. 2015 21:07, "Franklin? Lee" <leewangzhong+python@gmail.com> a écrit :

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Tim Peters points out how it might be more expensive than a lookup.

Your whole idea rely on the assumption than a dict lookup (two lookups for builtins) is slow. Remember that a dict lookup has a complexity of O(1)! That's why I suggested you to start to benchmark, especially know the time in nanoseconds of a dict lookup.

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He ended up using versioning, because the notification was expensive.

Yeah I also began with notification with a registry of functions before moving to versionning: http://faster-cpython.readthedocs.org/readonly.html

Versionning is simple to implement and doesn't make dict operations slower.

Victor