diff --git a/src/rewrite/Att.cpp b/src/rewrite/Att.cpp
index 8bd34fb1f..1082d77ad 100644
--- a/src/rewrite/Att.cpp
+++ b/src/rewrite/Att.cpp
@@ -152,3 +152,17 @@ bool Att::internal () const
 }
 
 ////////////////////////////////////////////////////////////////////////////////
+// TODO Encode values prior to serialization.
+void Att::encode (std::string&) const
+{
+  throw std::string ("unimplemented Att::internal");
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TODO Decode values after parse.
+void Att::decode (std::string&) const
+{
+  throw std::string ("unimplemented Att::internal");
+}
+
+////////////////////////////////////////////////////////////////////////////////
diff --git a/src/rewrite/Att.h b/src/rewrite/Att.h
index 2dd8ac8c2..e496a9261 100644
--- a/src/rewrite/Att.h
+++ b/src/rewrite/Att.h
@@ -57,6 +57,10 @@ public:
   bool required () const;
   bool internal () const;
 
+private:
+  void encode (std::string&) const;
+  void decode (std::string&) const;
+
 private:
   std::string mName;
   std::string mValue;