# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1338764582 -7200
# Node ID 814bd122d84d5bdcdb96fdba004e3ebd8879de7e
# Parent  e6f70a977e09a367bbbffa17f61c4a11d2022973
Updated the documentation to reflect class attribute assignment policies.
Added tests to demonstrate class attribute rebinding.

diff -r e6f70a977e09 -r 814bd122d84d docs/assignment.txt
--- a/docs/assignment.txt	Sun Jun 03 20:50:19 2012 +0200
+++ b/docs/assignment.txt	Mon Jun 04 01:03:02 2012 +0200
@@ -37,10 +37,9 @@
   local                             preserved           StoreName
   global (module)                   preserved           StoreAddress            StoreAttrIndex
   instance                          preserved           StoreAttr               StoreAttrIndex
-  class                             -> class            StoreAddressContext
+  class                             -> class            StoreAddressContext	StoreAttrIndex
 
-  Class assignments are not permitted except during initialisation and hence
-  employ no unoptimised instruction
+  Assignment of new class attributes is only permitted during initialisation
 
 Access types:
 
diff -r e6f70a977e09 -r 814bd122d84d docs/concepts.txt
--- a/docs/concepts.txt	Sun Jun 03 20:50:19 2012 +0200
+++ b/docs/concepts.txt	Mon Jun 04 01:03:02 2012 +0200
@@ -33,6 +33,14 @@
 a class as a key to the object table, where the full name is a qualified path
 via the module hierarchy ending with the name of the class.
 
+Rebinding of attributes outside classes and modules can be allowed if
+attribute usage observations are being used to detect such external
+modifications to such objects. Without such observations, such rebinding
+should be forbidden since apparently constant attributes might be modified in
+a running program, but code may have been generated that provides specific
+objects for those attributes under the assumption that they will not be
+changed.
+
 See rejected.txt for complicating mechanisms which could be applied to
 mitigate the effects of these restrictions on optimisations.
 
diff -r e6f70a977e09 -r 814bd122d84d tests/attributes_class_rebind.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/attributes_class_rebind.py	Mon Jun 04 01:03:02 2012 +0200
@@ -0,0 +1,12 @@
+#!/usr/bin/env python
+
+class C:
+    e = 123
+
+def f(obj):
+    obj.e = 456 # should rebind C.e
+
+f(C)
+result_456 = C.e
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r e6f70a977e09 -r 814bd122d84d tests/attributes_class_rebind_ambiguous.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/attributes_class_rebind_ambiguous.py	Mon Jun 04 01:03:02 2012 +0200
@@ -0,0 +1,17 @@
+#!/usr/bin/env python
+
+class C:
+    e = 123
+
+class F:
+    def __init__(self):
+        self.e = 789
+
+def f(obj):
+    obj.e = 456 # should rebind C.e
+
+other = F()
+f(C)
+result_456 = C.e
+
+# vim: tabstop=4 expandtab shiftwidth=4