Imported existing code

libraries/include/boost/python/detail/enable_if.hpp

@@ -0,0 +1,72 @@
+// Copyright David Abrahams 2004. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#ifndef ENABLE_IF_DWA2004722_HPP
+# define ENABLE_IF_DWA2004722_HPP
+
+# include <boost/python/detail/sfinae.hpp>
+# include <boost/detail/workaround.hpp>
+
+# if BOOST_WORKAROUND(BOOST_MSVC, <= 1300)
+#  include <boost/mpl/if.hpp>
+
+namespace boost { namespace python { namespace detail { 
+
+template <class T> struct always_void { typedef void type; };
+
+template <class C, class T = int>
+struct enable_if_arg
+{
+    typedef typename mpl::if_<C,T,int&>::type type;
+};
+             
+template <class C, class T = int>
+struct disable_if_arg
+{
+    typedef typename mpl::if_<C,int&,T>::type type;
+};
+             
+template <class C, class T = typename always_void<C>::type>
+struct enable_if_ret
+{
+    typedef typename mpl::if_<C,T,int[2]>::type type;
+};
+             
+template <class C, class T = typename always_void<C>::type>
+struct disable_if_ret
+{
+    typedef typename mpl::if_<C,int[2],T>::type type;
+};
+             
+}}} // namespace boost::python::detail
+
+# elif !defined(BOOST_NO_SFINAE)
+#  include <boost/utility/enable_if.hpp>
+
+namespace boost { namespace python { namespace detail { 
+
+template <class C, class T = int>
+struct enable_if_arg
+  : enable_if<C,T>
+{};
+             
+template <class C, class T = int>
+struct disable_if_arg
+  : disable_if<C,T>
+{};
+             
+template <class C, class T = void>
+struct enable_if_ret
+  : enable_if<C,T>
+{};
+             
+template <class C, class T = void>
+struct disable_if_ret
+  : disable_if<C,T>
+{};
+             
+}}} // namespace boost::python::detail
+
+# endif
+
+#endif // ENABLE_IF_DWA2004722_HPP