- merged -r4458:4466 of query_columns branch

- this branch changes query.values() to immediately return an iterator, adds a new "aliased" construct which will be the primary method to get at aliased columns when using values()
- tentative ORM versions of _join and _outerjoin are not yet public, would like to integrate with Query better (work continues in the branch)
- lots of fixes to expressions regarding cloning and correlation.  Some apparent ORM bug-workarounds removed.
- to fix a recursion issue with anonymous identifiers, bind parameters generated against columns now just use the name of the column instead of the tablename_columnname label (plus the unique integer counter).  this way expensive recursive schemes aren't needed for the anon identifier logic.   This, as usual, impacted a ton of compiler unit tests which needed a search-n-replace for the new bind names.

1 files changed, 8 insertions, 1 deletions

diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py
index 7eccc9b89..792391929 100644
--- a/lib/sqlalchemy/sql/visitors.py
+++ b/lib/sqlalchemy/sql/visitors.py
@@ -161,7 +161,14 @@ class NoColumnVisitor(ClauseVisitor):
     
     __traverse_options__ = {'column_collections':False}
 
-
+class NullVisitor(ClauseVisitor):
+    def traverse(self, obj, clone=False):
+        next = getattr(self, '_next', None)
+        if next:
+            return next.traverse(obj, clone=clone)
+        else:
+            return obj
+        
 def traverse(clause, **kwargs):
     """traverse the given clause, applying visit functions passed in as keyword arguments."""