python-checkins at python
Feb 28, 2012, 12:40 PM
peps: Update from Mark Shannon.
user: Martin v. Löwis <martin [at] v>
date: Tue Feb 28 21:40:37 2012 +0100
Update from Mark Shannon.
pep-0412.txt | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/pep-0412.txt b/pep-0412.txt
@@ -149,6 +149,25 @@
The iteration order of dictionaries was never defined and has always been
arbitrary; it is different for Jython and PyPy.
+An alternative implementation for split tables, which could save even more
+memory, is to store an index in the value field of the keys table (instead
+of ignoring the value field). This index would explicitly state where in the
+value array to look. The value array would then only require 1 field for each
+usable slot in the key table, rather than each slot in the key table.
+This "indexed" version would reduce the size of value array by about
+one third. The keys table would need an extra "values_size" field, increasing
+the size of combined dicts by one word.
+The extra indirection adds more complexity to the code, potentially reducing
+performance a little.
+The "indexed" version will not be included in this implementation,
+but should be considered deferred rather than rejected,
+pending further experimentation.
Repository URL: http://hg.python.org/peps