+#include <boost/preprocessor/arithmetic/inc.hpp>
+#include <boost/preprocessor/repetition/enum_binary_params.hpp>
+#include <boost/preprocessor/repetition/enum_params.hpp>
+#include <boost/preprocessor/repetition/repeat_from_to.hpp>
+
+
+// Base-from-member arity configuration macro ------------------------------//
+
+// The following macro determines how many arguments will be in the largest
+// constructor template of base_from_member. Constructor templates will be
+// generated from one argument to this maximum. Code from other files can read
+// this number if they need to always match the exact maximum base_from_member
+// uses. The maximum constructor length can be changed by overriding the
+// #defined constant. Make sure to apply the override, if any, for all source
+// files during project compiling for consistency.
+
+// Contributed by Jonathan Turkanis
+
+#ifndef BOOST_BASE_FROM_MEMBER_MAX_ARITY
+#define BOOST_BASE_FROM_MEMBER_MAX_ARITY 10
+#endif
+
+
+// An iteration of a constructor template for base_from_member -------------//
+
+// A macro that should expand to:
+// template < typename T1, ..., typename Tn >
+// base_from_member( T1 x1, ..., Tn xn )
+// : member( x1, ..., xn )
+// {}
+// This macro should only persist within this file.
+
+#define BOOST_PRIVATE_CTR_DEF( z, n, data ) \
+ template < BOOST_PP_ENUM_PARAMS(n, typename T) > \
+ explicit base_from_member( BOOST_PP_ENUM_BINARY_PARAMS(n, T, x) ) \
+ : member( BOOST_PP_ENUM_PARAMS(n, x) ) \
+ {} \
+ /**/