removing more duplication

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/arel/algebra/ordering.rb b/lib/arel/algebra/ordering.rb
index 984327aaf7..8ed3e1e6e6 100644
--- a/lib/arel/algebra/ordering.rb
+++ b/lib/arel/algebra/ordering.rb
@@ -13,10 +13,23 @@ module Arel
     def == other
       super || (self.class === other && attribute == other.attribute)
     end
+
+    def eval(row1, row2)
+      (attribute.eval(row1) <=> attribute.eval(row2)) * direction
+    end
+
+    def to_sql(formatter = Sql::OrderClause.new(relation))
+      formatter.ordering self
+    end
   end
 
   class Ascending  < Ordering
+    def direction; 1 end
+    def direction_sql; 'ASC' end
   end
+
   class Descending < Ordering
+    def direction_sql; 'DESC' end
+    def direction; -1 end
   end
 end