adding a base class visitor

3 files changed, 22 insertions, 10 deletions

diff --git a/lib/arel/visitors.rb b/lib/arel/visitors.rb
index fc585c39bb..01c6647039 100644
--- a/lib/arel/visitors.rb
+++ b/lib/arel/visitors.rb
@@ -1,3 +1,4 @@
+require 'arel/visitors/visitor'
 require 'arel/visitors/to_sql'
 require 'arel/visitors/postgresql'
 require 'arel/visitors/mysql'
diff --git a/lib/arel/visitors/to_sql.rb b/lib/arel/visitors/to_sql.rb
index 17779b4037..e68890004a 100644
--- a/lib/arel/visitors/to_sql.rb
+++ b/lib/arel/visitors/to_sql.rb
@@ -3,7 +3,7 @@ require 'date'
 
 module Arel
   module Visitors
-    class ToSql
+    class ToSql < Arel::Visitors::Visitor
       def initialize engine
         @engine         = engine
         @connection     = nil
@@ -16,7 +16,7 @@ module Arel
         @last_column = nil
         @engine.connection_pool.with_connection do |conn|
           @connection = conn
-          visit object
+          super
         end
       end
 
@@ -277,14 +277,6 @@ module Arel
       alias :visit_Time :visit_String
       alias :visit_TrueClass :visit_String
 
-      DISPATCH = Hash.new do |hash, klass|
-        hash[klass] = "visit_#{klass.name.gsub('::', '_')}"
-      end
-
-      def visit object
-        send DISPATCH[object.class], object
-      end
-
       def quote value, column = nil
         @connection.quote value, column
       end
diff --git a/lib/arel/visitors/visitor.rb b/lib/arel/visitors/visitor.rb
new file mode 100644
index 0000000000..510d50399b
--- /dev/null
+++ b/lib/arel/visitors/visitor.rb
@@ -0,0 +1,19 @@
+module Arel
+  module Visitors
+    class Visitor
+      def accept object
+        visit object
+      end
+
+      private
+
+      DISPATCH = Hash.new do |hash, klass|
+        hash[klass] = "visit_#{klass.name.gsub('::', '_')}"
+      end
+
+      def visit object
+        send DISPATCH[object.class], object
+      end
+    end
+  end
+end