4 files changed, 26 insertions, 17 deletions
diff --git a/lib/arel/collectors/plain_string.rb b/lib/arel/collectors/plain_string.rb
new file mode 100644
index 0000000000..2505bc376e
--- /dev/null
+++ b/lib/arel/collectors/plain_string.rb
@@ -0,0 +1,18 @@
+module Arel
+  module Collectors
+    class PlainString
+      def initialize
+        @str = ''
+      end
+
+      def value
+        @str
+      end
+
+      def << str
+        @str << str
+        self
+      end
+    end
+  end
+end
diff --git a/lib/arel/collectors/sql_string.rb b/lib/arel/collectors/sql_string.rb
index 45001bb507..8ca89ca7bd 100644
--- a/lib/arel/collectors/sql_string.rb
+++ b/lib/arel/collectors/sql_string.rb
@@ -1,21 +1,10 @@
 # encoding: utf-8
 
+require 'arel/collectors/plain_string'
+
 module Arel
   module Collectors
-    class SQLString
-      def initialize
-        @str = ''
-      end
-
-      def value
-        @str
-      end
-
-      def << str
-        @str << str
-        self
-      end
-
+    class SQLString < PlainString
       def add_bind bind
         self << bind.to_s
         self
diff --git a/lib/arel/tree_manager.rb b/lib/arel/tree_manager.rb
index 87887800d0..8bff97af78 100644
--- a/lib/arel/tree_manager.rb
+++ b/lib/arel/tree_manager.rb
@@ -15,7 +15,9 @@ module Arel
     end
 
     def to_dot
-      Visitors::Dot.new.accept @ast
+      collector = Arel::Collectors::PlainString.new
+      collector = Visitors::Dot.new.accept @ast, collector
+      collector.value
     end
 
     def visitor
diff --git a/lib/arel/visitors/dot.rb b/lib/arel/visitors/dot.rb
index ba35223ac9..d96cf7a6a0 100644
--- a/lib/arel/visitors/dot.rb
+++ b/lib/arel/visitors/dot.rb
@@ -22,9 +22,9 @@ module Arel
         @seen       = {}
       end
 
-      def accept object
+      def accept object, collector
         visit object
-        to_dot
+        collector << to_dot
       end
 
       private