diff --git a/include/boost/concept_archetype.hpp b/include/boost/concept_archetype.hpp
index 3bf72e4..41b4e55 100644
--- a/include/boost/concept_archetype.hpp
+++ b/include/boost/concept_archetype.hpp
@@ -17,6 +17,7 @@
 
 #include <boost/config.hpp>
 #include <boost/iterator.hpp>
+#include <boost/mpl/identity.hpp>
 #include <functional>
 
 namespace boost {
@@ -258,25 +259,25 @@ namespace boost {
   struct optag2 { };
   struct optag3 { };
 
-#define BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(OP, NAME) \
-  template <class Base = null_archetype<>, class Tag = optag1 > \
-  class NAME##_first_archetype : public Base { \
-  public: \
-    NAME##_first_archetype(detail::dummy_constructor x) : Base(x) { } \
-  }; \
-  \
-  template <class Base = null_archetype<>, class Tag = optag1 > \
-  class NAME##_second_archetype : public Base { \
-  public: \
-    NAME##_second_archetype(detail::dummy_constructor x) : Base(x) { } \
-  }; \
-  \
-  template <class BaseFirst, class BaseSecond, class Tag> \
-  boolean_archetype \
-  operator OP (const NAME##_first_archetype<BaseFirst, Tag>&, \
-               const NAME##_second_archetype<BaseSecond, Tag>&) \
-  { \
-   return boolean_archetype(static_object<detail::dummy_constructor>::get()); \
+#define BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(OP, NAME)                       \
+  template <class Base = null_archetype<>, class Tag = optag1 >                 \
+  class NAME##_first_archetype : public Base {                                  \
+  public:                                                                       \
+    NAME##_first_archetype(detail::dummy_constructor x) : Base(x) { }           \
+  };                                                                            \
+                                                                                \
+  template <class Base = null_archetype<>, class Tag = optag1 >                 \
+  class NAME##_second_archetype : public Base {                                 \
+  public:                                                                       \
+    NAME##_second_archetype(detail::dummy_constructor x) : Base(x) { }          \
+  };                                                                            \
+                                                                                \
+  template <class BaseFirst, class BaseSecond, class Tag>                       \
+  boolean_archetype                                                             \
+  operator OP (const NAME##_first_archetype<BaseFirst, Tag>&,                   \
+               const NAME##_second_archetype<BaseSecond, Tag>&)                 \
+  {                                                                             \
+   return boolean_archetype(static_object<detail::dummy_constructor>::get());   \
   }
 
   BOOST_DEFINE_BINARY_PREDICATE_ARCHETYPE(==, equal_op)