OR nodes are somewhat working

lib/arel/nodes.rb

@@ -1,4 +1,7 @@
+require 'arel/nodes/binary'
 require 'arel/nodes/equality'
+require 'arel/nodes/or'
+
 require 'arel/nodes/in'
 require 'arel/nodes/sql_literal'
 require 'arel/nodes/select_core'

lib/arel/nodes/binary.rb

@@ -0,0 +1,24 @@
+module Arel
+  module Nodes
+    class Binary
+      attr_accessor :left, :right
+
+      def initialize left, right
+        @left  = left
+        @right = right
+      end
+
+      def or right
+        Nodes::Or.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.
+      def to_sql
+        viz = Visitors::ToSql.new left.relation.engine
+        viz.accept self
+      end
+    end
+  end
+end

lib/arel/nodes/equality.rb

@@ -1,17 +1,6 @@
 module Arel
   module Nodes
-    class Equality
-      attr_accessor :left, :right
-
-      def initialize left, right
-        @left  = left
-        @right = right
-      end
-
-      def to_sql
-        viz = Visitors::ToSql.new left.relation.engine
-        viz.accept self
-      end
+    class Equality < Arel::Nodes::Binary
     end
   end
 end

lib/arel/nodes/or.rb

@@ -0,0 +1,6 @@
+module Arel
+  module Nodes
+    class Or < Arel::Nodes::Binary
+    end
+  end
+end

lib/arel/visitors/to_sql.rb

@@ -60,6 +60,10 @@ module Arel
         "#{visit o.left} IN (#{o.right.map { |x| quote visit x }.join ', '})"
       end
 
+      def visit_Arel_Nodes_Or o
+        "#{visit o.left} OR #{visit o.right}"
+      end
+
       def visit_Arel_Nodes_Equality o
         "#{visit o.left} = #{quote visit o.right}"
       end

spec/arel/nodes/equality_spec.rb

@@ -0,0 +1,16 @@
+module Arel
+  module Nodes
+    describe 'equality' do
+      describe 'or' do
+        it 'makes an OR node' do
+          attr = Table.new(:users)[:id]
+          left  = attr.eq(10)
+          right = attr.eq(11)
+          node  = left.or right
+          check node.left.should == left
+          check node.right.should == right
+        end
+      end
+    end
+  end
+end

spec/arel/nodes/or_spec.rb

@@ -0,0 +1,20 @@
+module Arel
+  module Nodes
+    describe 'or' do
+      describe '#or' do
+        it 'makes an OR node' do
+          attr = Table.new(:users)[:id]
+          left  = attr.eq(10)
+          right = attr.eq(11)
+          node  = left.or right
+          check node.left.should == left
+          check node.right.should == right
+
+          oror = node.or(right)
+          check oror.left == node
+          check oror.right == right
+        end
+      end
+    end
+  end
+end

spec/arel/visitors/to_sql_spec.rb

@@ -8,6 +8,13 @@ module Arel
         @attr = Table.new(:users)[:id]
       end
 
+      it "should visit_Arel_Nodes_Or" do
+        node = Nodes::Or.new @attr.eq(10), @attr.eq(11)
+        @visitor.accept(node).should be_like %{
+          "users"."id" = 10 OR "users"."id" = 11
+        }
+      end
+
       it "should visit visit_Arel_Attributes_Time" do
         attr = Attributes::Time.new(@attr.relation, @attr.name, @attr.column)
         @visitor.accept attr