整理

include/boost/preprocessor/seq/detail/is_empty.hpp

@@ -0,0 +1,49 @@
+# /* **************************************************************************
+#  *                                                                          *
+#  *     (C) Copyright Edward Diener 2015.
+#  *     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)
+#  *                                                                          *
+#  ************************************************************************** */
+#
+# /* See http://www.boost.org for most recent version. */
+#
+# ifndef BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
+# define BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
+#
+# include <boost/preprocessor/config/config.hpp>
+# include <boost/preprocessor/arithmetic/dec.hpp>
+# include <boost/preprocessor/logical/bool.hpp>
+# include <boost/preprocessor/logical/compl.hpp>
+# include <boost/preprocessor/seq/size.hpp>
+#
+/* An empty seq is one that is just BOOST_PP_SEQ_NIL */
+#
+# define BOOST_PP_SEQ_DETAIL_IS_EMPTY(seq) \
+    BOOST_PP_COMPL \
+        ( \
+        BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
+        ) \
+/**/
+#
+# define BOOST_PP_SEQ_DETAIL_IS_EMPTY_SIZE(size) \
+    BOOST_PP_COMPL \
+        ( \
+        BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
+        ) \
+/**/
+#
+# define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
+    BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq)) \
+/**/
+#
+# define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
+    BOOST_PP_BOOL(size) \
+/**/
+#
+# define BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq) \
+    BOOST_PP_DEC(BOOST_PP_SEQ_SIZE(seq (nil))) \
+/**/
+#
+# endif