[Python-Dev] Idea: Dictionary references

[Victor Stinner]

Le vendredi 18 décembre 2015, Andrew Barnert via Python-Dev <
python-dev at python.org> a écrit :
>
> >> Builtins do two dict lookups.
> >
> > Two?
>
> Actually, I guess three: first you fail to find the name in globals, then
> you find __builtins__ in globals, then you find the name in __builtins__ or
> __builtins__.__dict__.
>

Getting builtins from globals in done when the frame object is created, and
the lookup is skipped in the common case if qu recall correctly. LOAD_NAME
does a lookup on function globals, if the key doesn't exist (common case
for builtins), a ceond lookup is done in frame builtins. Open
Python/ceval.c and see to code. There is an optimisation for fast lookup in
two dict.

Victor
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