[Python-Dev] Draft proposal: Implicit self in Python 3.0 (original) (raw)

Thomas Wouters thomas at xs4all.net
Sun Jan 8 17:26:59 CET 2006

On Sun, Jan 08, 2006 at 08:09:22AM -0800, Ralf W. Grosse-Kunstleve wrote:

--- Thomas Wouters <thomas at xs4all.net> wrote: > The main difference isn't the lookup of 'self', it's the attribute retrieval > of 'x' from 'self'.

I see. Thanks! If you put 'self' into a special category (with corresponding C code), couldn't you use the same "indexing" tricks as for local variables and make 'self.x' just as fast as 'x'?

No need to make 'self' magical for that. You do, however, need to make the object magical for that. It works for local namespaces because the Python compiler knows exactly which names are local and which aren't. There are two cases where the compiler can't know for sure (using 'exec' without 'in' and using 'from module import *') and in those cases, Python doesn't optimize local variable access all the way. This all won't work for objects and their attributes because too much is possible at runtime for the current compiler to handle.

The compiler could, of course, check everything in the whole program, keeping track of what could possibly adjust which attributes of what object where. That would be 'type inferencing' and has been (and is being, I guess) attempted by various people in various projets. However, if your compiler is so smart, it won't have any problems taking an exlicit self into account :)

-- Thomas Wouters <thomas at xs4all.net>

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