diff --git a/CMakeLists.txt b/CMakeLists.txt
index c71bfa7..1c748eb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,7 +13,7 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 
 set(b_modules
 	core ds serial term cmd io compress
-	core-mm)
+	core-mm ds-mm)
 
 set(b_system_name ${CMAKE_SYSTEM_NAME})
 string(TOLOWER ${b_system_name} b_system_name)
diff --git a/ds-mm/CMakeLists.txt b/ds-mm/CMakeLists.txt
new file mode 100644
index 0000000..ff2eb60
--- /dev/null
+++ b/ds-mm/CMakeLists.txt
@@ -0,0 +1,5 @@
+include(../cmake/Templates.cmake)
+
+add_bluelib_mm_module(
+	NAME ds
+	DEPENDENCIES core-mm ds)
diff --git a/ds-mm/include/blue/core.hpp b/ds-mm/include/blue/core.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/ds-mm/include/blue/ds.hpp b/ds-mm/include/blue/ds.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/ds-mm/include/blue/ds/string.hpp b/ds-mm/include/blue/ds/string.hpp
new file mode 100644
index 0000000..37fd16d
--- /dev/null
+++ b/ds-mm/include/blue/ds/string.hpp
@@ -0,0 +1,63 @@
+#ifndef BLUE_DS_STRING_HPP_
+#define BLUE_DS_STRING_HPP_
+
+#include <blue/core/encoding.hpp>
+#include <blue/core/object.hpp>
+#include <blue/core/status.hpp>
+#include <blue/core/stringstream.hpp>
+#include <cstddef>
+
+namespace blue::ds
+{
+class string : public core::object
+{
+    public:
+	core::type get_type(void);
+
+	string();
+	string(const char *s);
+	string(const core::wchar *s);
+	string(char c, std::size_t count);
+
+	char *steal(void);
+	status reserve(size_t capacity);
+	status replace(size_t start, size_t len, const char *new_data);
+	status replace(const char *new_data);
+	status replace(const core::stringstream &new_data);
+	status remove(size_t start, size_t len);
+	status transform(int (*transformer)(int));
+	status trim(void);
+	status toupper(void)
+	{
+		return transform(::toupper);
+	}
+
+	status tolower(void)
+	{
+		return transform(::tolower);
+	}
+
+	status append(char c);
+	status append(core::wchar c);
+	status append(const string &s);
+	status append(const core::wchar *s);
+	status append(const char *format, ...);
+
+	status prepend(char c);
+	status prepend(core::wchar c);
+	status prepend(const char *s);
+	status prepend(const core::wchar *s);
+	status prepend(const char *format, ...);
+
+	status insert(char c, std::size_t at);
+	status insert(core::wchar c, std::size_t at);
+	status insert(const string &s, std::size_t at);
+	status insert(const char *s, std::size_t at);
+	status insert(const core::wchar *s, std::size_t at);
+	status insert(std::size_t at, const char *format, ...);
+
+	void clear(void);
+};
+}
+
+#endif
diff --git a/ds-mm/string.cpp b/ds-mm/string.cpp
new file mode 100644
index 0000000..e69de29