adding a grouping node

3 files changed, 42 insertions, 9 deletions

diff --git a/lib/arel/nodes/binary.rb b/lib/arel/nodes/binary.rb
index 3cd9583e79..090468adfa 100644
--- a/lib/arel/nodes/binary.rb
+++ b/lib/arel/nodes/binary.rb
@@ -1,6 +1,6 @@
 module Arel
   module Nodes
-    class Binary
+    class Binary < Arel::Nodes::Node
       attr_accessor :left, :right
 
       def initialize left, right
@@ -8,14 +8,6 @@ module Arel
         @right = right
       end
 
-      def or right
-        Nodes::Or.new self, right
-      end
-
-      def and right
-        Nodes::And.new self, right
-      end
-
       # FIXME: this method should go away.  I don't like people calling
       # to_sql on non-head nodes.  This forces us to walk the AST until we
       # can find a node that has a "relation" member.
diff --git a/lib/arel/nodes/grouping.rb b/lib/arel/nodes/grouping.rb
new file mode 100644
index 0000000000..0af1df1f7a
--- /dev/null
+++ b/lib/arel/nodes/grouping.rb
@@ -0,0 +1,21 @@
+module Arel
+  module Nodes
+    class Grouping < Arel::Nodes::Node
+      attr_accessor :expr
+
+      def initialize expression
+        @expr = expression
+      end
+
+      # FIXME: this method should go away.  I don't like people calling
+      # to_sql on non-head nodes.  This forces us to walk the AST until we
+      # can find a node that has a "relation" member.
+      #
+      # Maybe we should just use `Table.engine`?  :'(
+      def to_sql
+        viz = Visitors::ToSql.new Table.engine
+        viz.accept self
+      end
+    end
+  end
+end
diff --git a/lib/arel/nodes/node.rb b/lib/arel/nodes/node.rb
new file mode 100644
index 0000000000..fd5ea410ea
--- /dev/null
+++ b/lib/arel/nodes/node.rb
@@ -0,0 +1,20 @@
+module Arel
+  module Nodes
+    ###
+    # Abstract base class for all AST nodes
+    class Node
+      ###
+      # Factory method to create a Nodes::Grouping node that has an Nodes::Or
+      # node as a child.
+      def or right
+        Nodes::Grouping.new Nodes::Or.new(self, right)
+      end
+
+      ###
+      # Factory method to create an Nodes::And node.
+      def and right
+        Nodes::And.new self, right
+      end
+    end
+  end
+end