[Python-Dev] Making None a keyword

[Fred L. Drake, Jr.]

Jeremy Hylton writes:
 > I don't understand what you mean, but I'll try to reply anyway :-).

Often a good tactic.  ;-)

 > I assume LOAD_NONE will eliminate the need for LOAD_CONST 0 (None).

Yes.

 > It's probably a wee bit faster and it makes the bytecode smaller,
 > because you don't need None in co_consts and you don't need an
 > argument to the bytecode.

Yes.

 > Based on my cycle counter measurements before the conference, I
 > suspect the performance impact is, well, negligible.

Regarding changing LOAD_CONST 0 to LOAD_NONE, yes.  What's more
interesting are the changes of LOAD_GLOBAL 'None' to one of LOAD_CONST
0 or LOAD_NONE.  That could be changed to use LOAD_CONST 0 *now*,
without adding a new bytecode, and we could get a better idea of how
much performance it actually buys us in practice, since we get rid of
two dict lookups (globals & builtins).

That doesn't address the deprecation cycle, but it would be nice to
see what the change would buy us.


  -Fred

-- 
Fred L. Drake, Jr.  <fdrake at acm.org>
PythonLabs at Zope Corporation