- parenthesis are applied to clauses via a new _Grouping construct.

uses operator precedence to more intelligently apply parenthesis
to clauses, provides cleaner nesting of clauses (doesnt mutate
clauses placed in other clauses, i.e. no 'parens' flag)
- added 'modifier' keyword, works like func.<foo> except does not
add parenthesis.  e.g. select([modifier.DISTINCT(...)]) etc.

1 files changed, 12 insertions, 5 deletions

diff --git a/lib/sqlalchemy/sql_util.py b/lib/sqlalchemy/sql_util.py
index dcd19f891..1f5ac1681 100644
--- a/lib/sqlalchemy/sql_util.py
+++ b/lib/sqlalchemy/sql_util.py
@@ -133,16 +133,23 @@ class AbstractClauseProcessor(sql.NoColumnVisitor):
                 list_[i] = elem
             else:
                 self.traverse(list_[i])
-
-    def visit_compound(self, compound):
-        self.visit_clauselist(compound)
-
+    
+    def visit_grouping(self, grouping):
+        elem = self.convert_element(grouping.elem)
+        if elem is not None:
+            grouping.elem = elem
+            
     def visit_clauselist(self, clist):
         for i in range(0, len(clist.clauses)):
             n = self.convert_element(clist.clauses[i])
             if n is not None:
                 clist.clauses[i] = n
-
+    
+    def visit_unary(self, unary):
+        elem = self.convert_element(unary.element)
+        if elem is not None:
+            unary.element = elem
+            
     def visit_binary(self, binary):
         elem = self.convert_element(binary.left)
         if elem is not None: