diff --git a/src/yycc/num/stringify.hpp b/src/yycc/num/stringify.hpp
index 1a048be..3ae2492 100644
--- a/src/yycc/num/stringify.hpp
+++ b/src/yycc/num/stringify.hpp
@@ -40,6 +40,7 @@ namespace yycc::num::stringify {
                                        std::chars_format fmt = std::chars_format::general,
                                        int precision = 6) {
         namespace reinterpret = NS_YYCC_STRING_REINTERPRET;
+
         StringifyBuffer buffer;
         auto [ptr, ec] = std::to_chars(reinterpret::as_ordinary(buffer.data()),
                                        reinterpret::as_ordinary(buffer.data() + buffer.size()),
@@ -67,6 +68,7 @@ namespace yycc::num::stringify {
     template<typename T, std::enable_if_t<std::is_integral_v<T> && !std::is_same_v<T, bool>, int> = 0>
     NS_YYCC_STRING::u8string stringify(T num, int base = 10) {
         namespace reinterpret = NS_YYCC_STRING_REINTERPRET;
+        
         StringifyBuffer buffer;
         auto [ptr, ec] = std::to_chars(reinterpret::as_ordinary(buffer.data()),
                                        reinterpret::as_ordinary(buffer.data() + buffer.size()),
diff --git a/src/yycc/string.hpp b/src/yycc/string.hpp
index 64f0d13..f1f2f20 100644
--- a/src/yycc/string.hpp
+++ b/src/yycc/string.hpp
@@ -39,4 +39,9 @@ namespace yycc::string {
     using u8string = std::basic_string<u8char>;
     using u8string_view = std::basic_string_view<u8char>;
 #endif
+
+#define _YYCC_U8(strl) u8 ## strl ///< The assistant macro for YYCC_U8.
+#define YYCC_U8(strl) (reinterpret_cast<const ::yycc::string::u8char*>(_YYCC_U8(strl))) ///< The macro for creating UTF8 string literal. See \ref library_encoding.
+#define YYCC_U8_CHAR(chr) (static_cast<::yycc::string::u8char>(chr)) ///< The macro for casting ordinary char type into YYCC UTF8 char type.
+
 } // namespace yycc::string
diff --git a/src/yycc/string/op.cpp b/src/yycc/string/op.cpp
index c277110..0916321 100644
--- a/src/yycc/string/op.cpp
+++ b/src/yycc/string/op.cpp
@@ -19,6 +19,8 @@ namespace yycc::string::op {
 	}
 
 	bool vprintf(NS_YYCC_STRING::u8string& strl, const NS_YYCC_STRING::u8char* format, va_list argptr) {
+        namespace reinterpret = NS_YYCC_STRING_REINTERPRET;
+
 		va_list args1;
 		va_copy(args1, argptr);
 		va_list args2;
@@ -29,7 +31,7 @@ namespace yycc::string::op {
 		int count = std::vsnprintf(
 			nullptr,
 			0,
-			NS_YYCC_STRING_REINTERPRET::as_ordinary(format),
+			reinterpret::as_ordinary(format),
 			args1
 		);
 		if (count < 0) {
@@ -44,9 +46,9 @@ namespace yycc::string::op {
 		// however std::vsnprintf already have a trailing NULL, so we plus 1 for it.
 		strl.resize(count);
 		int write_result = std::vsnprintf(
-			NS_YYCC_STRING_REINTERPRET::as_ordinary(strl.data()),
+			reinterpret::as_ordinary(strl.data()),
 			strl.size() + 1,
-			NS_YYCC_STRING_REINTERPRET::as_ordinary(format),
+			reinterpret::as_ordinary(format),
 			args2
 		);
 		va_end(args2);
diff --git a/src/yycc/string/reinterpret.hpp b/src/yycc/string/reinterpret.hpp
index 9bab48f..e2d454b 100644
--- a/src/yycc/string/reinterpret.hpp
+++ b/src/yycc/string/reinterpret.hpp
@@ -12,10 +12,6 @@
  */
 namespace yycc::string::reinterpret {
 
-#define _YYCC_U8(strl) u8 ## strl ///< The assistant macro for YYCC_U8.
-#define YYCC_U8(strl) (reinterpret_cast<const ::yycc::string::u8char*>(_YYCC_U8(strl))) ///< The macro for creating UTF8 string literal. See \ref library_encoding.
-#define YYCC_U8_CHAR(chr) (static_cast<::yycc::string::u8char>(chr)) ///< The macro for casting ordinary char type into YYCC UTF8 char type.
-
 	/**
 	 * @brief Reinterpret ordinary C-string to UTF-8 string (const version).
 	 * @param src Source ordinary string
diff --git a/testbench/CMakeLists.txt b/testbench/CMakeLists.txt
index 2021aa6..08c99b5 100644
--- a/testbench/CMakeLists.txt
+++ b/testbench/CMakeLists.txt
@@ -15,6 +15,14 @@ PRIVATE
     yycc/patch/contains.cpp
     yycc/patch/starts_ends_with.cpp
 )
+target_sources(YYCCTestbench
+PRIVATE
+FILE_SET HEADERS
+FILES
+    shared/parse_template.hpp
+    shared/stringify_template.hpp
+    shared/utf_literal.hpp
+)
 # Setup headers
 target_include_directories(YYCCTestbench
 PUBLIC
diff --git a/testbench/shared/parse_template.hpp b/testbench/shared/parse_template.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/testbench/shared/stringify_template.hpp b/testbench/shared/stringify_template.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/testbench/shared/utf_literal.hpp b/testbench/shared/utf_literal.hpp
new file mode 100644
index 0000000..e69de29
diff --git a/testbench/yycc/constraint/builder.cpp b/testbench/yycc/constraint/builder.cpp
index 059e36c..f043533 100644
--- a/testbench/yycc/constraint/builder.cpp
+++ b/testbench/yycc/constraint/builder.cpp
@@ -1,7 +1,6 @@
 #include <gtest/gtest.h>
 #include <yycc.hpp>
 #include <yycc/constraint/builder.hpp>
-#include <yycc/string/reinterpret.hpp>
 
 #include <yycc/prelude/rust.hpp>
 
diff --git a/testbench/yycc/num/parse.cpp b/testbench/yycc/num/parse.cpp
index 18631f6..8bbda10 100644
--- a/testbench/yycc/num/parse.cpp
+++ b/testbench/yycc/num/parse.cpp
@@ -1,7 +1,6 @@
 #include <gtest/gtest.h>
 #include <yycc.hpp>
 #include <yycc/num/parse.hpp>
-#include <yycc/string/reinterpret.hpp>
 
 #include <yycc/prelude/rust.hpp>
 
diff --git a/testbench/yycc/num/stringify.cpp b/testbench/yycc/num/stringify.cpp
index 52850f6..27cd58c 100644
--- a/testbench/yycc/num/stringify.cpp
+++ b/testbench/yycc/num/stringify.cpp
@@ -1,7 +1,6 @@
 #include <gtest/gtest.h>
 #include <yycc.hpp>
 #include <yycc/num/stringify.hpp>
-#include <yycc/string/reinterpret.hpp>
 
 #include <yycc/prelude/rust.hpp>
 
diff --git a/testbench/yycc/string/op.cpp b/testbench/yycc/string/op.cpp
index 47453fa..f74638d 100644
--- a/testbench/yycc/string/op.cpp
+++ b/testbench/yycc/string/op.cpp
@@ -1,7 +1,6 @@
 #include <gtest/gtest.h>
 #include <yycc.hpp>
 #include <yycc/string/op.hpp>
-#include <yycc/string/reinterpret.hpp>
 
 #include <yycc/prelude/core.hpp>