- rewritten ClauseAdapter merged from the eager_minus_join branch; this is a much simpler

and "correct" version which will copy all elements exactly once, except for those which were
replaced with target elements.  It also can match a wider variety of target elements including
joins and selects on identity alone.

1 files changed, 6 insertions, 10 deletions

diff --git a/lib/sqlalchemy/sql/visitors.py b/lib/sqlalchemy/sql/visitors.py
index 98e4de6c3..bf15c2b7e 100644
--- a/lib/sqlalchemy/sql/visitors.py
+++ b/lib/sqlalchemy/sql/visitors.py
@@ -1,8 +1,7 @@
 class ClauseVisitor(object):
-    """A class that knows how to traverse and visit
-    ``ClauseElements``.
+    """Traverses and visits ``ClauseElement`` structures.
     
-    Calls visit_XXX() methods dynamically generated for each particualr
+    Calls visit_XXX() methods dynamically generated for each particular
     ``ClauseElement`` subclass encountered.  Traversal of a
     hierarchy of ``ClauseElements`` is achieved via the
     ``traverse()`` method, which is passed the lead
@@ -40,7 +39,7 @@ class ClauseVisitor(object):
                 traversal.insert(0, t)
                 for c in t.get_children(**self.__traverse_options__):
                     stack.append(c)
-        
+
     def traverse(self, obj, stop_on=None, clone=False):
         if clone:
             obj = obj._clone()
@@ -75,13 +74,10 @@ class ClauseVisitor(object):
         return self
 
 class NoColumnVisitor(ClauseVisitor):
-    """a ClauseVisitor that will not traverse the exported Column 
-    collections on Table, Alias, Select, and CompoundSelect objects
-    (i.e. their 'columns' or 'c' attribute).
+    """ClauseVisitor with 'column_collections' set to False; will not
+    traverse the front-facing Column collections on Table, Alias, Select, 
+    and CompoundSelect objects.
     
-    this is useful because most traversals don't need those columns, or
-    in the case of DefaultCompiler it traverses them explicitly; so
-    skipping their traversal here greatly cuts down on method call overhead.
     """
     
     __traverse_options__ = {'column_collections':False}