[Python-Dev] Global name lookup schemes

2002年2月17日 22:27:02 -0600 (CST)

Okay, i spent another afternoon drawing silly pictures full
of boxes and arrows. I swear, i'm going to be seeing pointers
in my dreams tonight.
Here are figures representing my current understanding of the
various schemes on the table:
 Jeremy 1: the dlict scheme
 http://lfw.org/python/jeremy1.gif
 http://lfw.org/python/jeremy1.tif
 http://lfw.org/python/jeremy1.ai
 Jeremy, i think i'm still somewhat unclear -- notice the
 two question marks in the figure. What kind of animal
 is the cache? I assumed that the invalidation info lives
 in an array parallel to the dlict's array. Is this right?
 Guido 1: the original cellptr/objptr scheme
 http://lfw.org/python/guido1.gif
 http://lfw.org/python/guido1.tif
 http://lfw.org/python/guido1.ai
 Ping 1: guido1 + a tweak to always use two dereferencing steps
 http://lfw.org/python/ping1.gif
 http://lfw.org/python/ping1.tif
 http://lfw.org/python/ping1.ai
 Tim 1: timdicts and cells with shadow flags
 http://lfw.org/python/tim1.gif
 http://lfw.org/python/tim1.tif
 http://lfw.org/python/tim1.ai
GIFs are small versions, TIFs are big versions, AIs are
Adobe Illustrator source files.
Please examine, send me corrections, discuss, enjoy... :)
Still to do:
 Guido 2: the globals_vector scheme
 Skip 1: the global-tracking scheme
 (I don't actually know yet what in this diagram
 would be different from the way things work today.
 Statically, Skip's picture is mostly the same;
 it's the runtime behaviour that's different.
 Still, it's probably good to have a reference
 picture of today's data structures anyway.)
-- ?!ng