diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7a03f9a..1775dd1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -36,7 +36,7 @@ if(BUILD_TESTS)
 	add_subdirectory(tests)
 endif()
 
-set(LIBREXY_PUBLIC_HEADERS "include/rexy/algorithm.hpp" "include/rexy/utility.hpp" "include/rexy/basic_string_hash.hpp" "include/rexy/hash.hpp" "include/rexy/static_string_hash.hpp" "include/rexy/string_hash.hpp" "include/rexy/mpmc_queue.hpp" "include/rexy/mpmc_queue.tpp" "include/rexy/traits.hpp" "include/rexy/steal.hpp" "include/rexy/binary.hpp" "include/rexy/expression.hpp" "include/rexy/binary_base.hpp" "include/rexy/binary_base.tpp" "include/rexy/string_base.hpp" "include/rexy/string.hpp" "include/rexy/filerd.hpp" "include/rexy/string_base.tpp" "include/rexy/allocator.hpp")
+set(LIBREXY_PUBLIC_HEADERS "include/rexy/algorithm.hpp" "include/rexy/utility.hpp" "include/rexy/basic_string_hash.hpp" "include/rexy/hash.hpp" "include/rexy/static_string_hash.hpp" "include/rexy/string_hash.hpp" "include/rexy/mpmc_queue.hpp" "include/rexy/mpmc_queue.tpp" "include/rexy/traits.hpp" "include/rexy/steal.hpp" "include/rexy/binary.hpp" "include/rexy/expression.hpp" "include/rexy/binary_base.hpp" "include/rexy/binary_base.tpp" "include/rexy/string_base.hpp" "include/rexy/string.hpp" "include/rexy/filerd.hpp" "include/rexy/string_base.tpp" "include/rexy/allocator.hpp" "include/rexy/meta.hpp")
 target_compile_options(rexy PRIVATE -Wall -Wextra -pedantic -std=c++17)
 
 install(TARGETS rexy
diff --git a/include/rexy/meta.hpp b/include/rexy/meta.hpp
new file mode 100644
index 0000000..4555ebf
--- /dev/null
+++ b/include/rexy/meta.hpp
@@ -0,0 +1,37 @@
+/**
+	This file is a part of rexy's general purpose library
+	Copyright (C) 2021 rexy712
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Affero General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef REXY_META_HPP
+#define REXY_META_HPP
+
+namespace rexy{
+
+	template<int... Is>
+	struct sequence_tuple{};
+	template<int I, int... Is>
+	struct sequence_gen : public sequence_gen<I-1, Is..., sizeof...(Is)>{};
+	template<int... Is>
+	struct sequence_gen<0,Is...>{
+		using type = sequence_tuple<Is...>;
+	};
+	template<int... Is>
+	using sequence_gen_t = typename sequence_gen<Is...>::type;
+
+}
+
+#endif
diff --git a/src/ensure.cpp b/src/ensure.cpp
index 351828a..16d6baa 100644
--- a/src/ensure.cpp
+++ b/src/ensure.cpp
@@ -16,6 +16,7 @@
 #include "rexy/string.hpp"
 #include "rexy/traits.hpp"
 #include "rexy/utility.hpp"
+#include "rexy/meta.hpp"
 
 #include "rexy/detail/binary_string_conv.hpp"
 #include "rexy/detail/string_appender.hpp"