...

16 files changed, 303 insertions, 279 deletions

diff --git a/src/base.hpp b/src/base.hpp
index a62a745b..2c511c4b 100644
--- a/src/base.hpp
+++ b/src/base.hpp
@@ -7,9 +7,6 @@
 #include <string_view>
 
 namespace cru {
-template <typename T>
-struct type_tag {};
-
 // typedefs
 using String = std::wstring;
 using MultiByteString = std::string;
@@ -38,9 +35,4 @@ struct Interface {
 [[noreturn]] inline void UnreachableCode() {
   throw std::logic_error("Unreachable code.");
 }
-
-inline void Require(const bool condition,
-                    const MultiByteStringView& error_message) {
-  if (!condition) throw std::invalid_argument(error_message.data());
-}
 }  // namespace cru
diff --git a/src/cru_debug.cpp b/src/cru_debug.cpp
index b9226132..331d2bce 100644
--- a/src/cru_debug.cpp
+++ b/src/cru_debug.cpp
@@ -3,7 +3,9 @@
 #include "system_headers.hpp"
 
 namespace cru::debug {
+#ifdef CRU_DEBUG
 void DebugMessage(const StringView& message) {
   ::OutputDebugStringW(message.data());
 }
+#endif
 }  // namespace cru::debug
diff --git a/src/cru_debug.hpp b/src/cru_debug.hpp
index 9c22a24f..58431d56 100644
--- a/src/cru_debug.hpp
+++ b/src/cru_debug.hpp
@@ -7,7 +7,11 @@
 #include "util/format.hpp"
 
 namespace cru::debug {
+#ifdef CRU_DEBUG
 void DebugMessage(const StringView& message);
+#else
+inline void DebugMessage(const StringView& message) {}
+#endif
 
 #ifdef CRU_DEBUG
 inline void DebugTime(const std::function<void()>& action,
diff --git a/src/ui/content_control.cpp b/src/ui/content_control.cpp
new file mode 100644
index 00000000..960867b2
--- /dev/null
+++ b/src/ui/content_control.cpp
@@ -0,0 +1,32 @@
+#include "content_control.hpp"
+
+#include "window.hpp"
+
+namespace cru::ui {
+ContentControl::ContentControl()
+    : child_vector_{nullptr}, child_(child_vector_[0]) {}
+
+ContentControl::~ContentControl() { delete child_; }
+
+void ContentControl::SetChild(Control* child) {
+  if (dynamic_cast<Window*>(child))
+    throw std::invalid_argument("Can't add a window as child.");
+
+  if (child == child_) return;
+
+  const auto window = GetWindow();
+  const auto old_child = child_;
+  child_ = child;
+  if (old_child) {
+    old_child->_SetParent(nullptr);
+    old_child->_SetDescendantWindow(nullptr);
+  }
+  if (child) {
+    child->_SetParent(this);
+    child->_SetDescendantWindow(window);
+  }
+  OnChildChanged(old_child, child);
+}
+
+void ContentControl::OnChildChanged(Control* old_child, Control* new_child) {}
+}  // namespace cru::ui
diff --git a/src/ui/content_control.hpp b/src/ui/content_control.hpp
new file mode 100644
index 00000000..88e7f60f
--- /dev/null
+++ b/src/ui/content_control.hpp
@@ -0,0 +1,31 @@
+#pragma once
+#include "pre.hpp"
+
+#include "control.hpp"
+
+namespace cru::ui {
+class ContentControl : public Control {
+ protected:
+  ContentControl();
+
+ public:
+  ContentControl(const ContentControl& other) = delete;
+  ContentControl(ContentControl&& other) = delete;
+  ContentControl& operator=(const ContentControl& other) = delete;
+  ContentControl& operator=(ContentControl&& other) = delete;
+  ~ContentControl() override;
+
+  const std::vector<Control*>& GetChildren() const override final {
+    return child_vector_;
+  }
+  Control* GetChild() const { return child_; }
+  void SetChild(Control* child);
+
+ protected:
+  virtual void OnChildChanged(Control* old_child, Control* new_child);
+
+ private:
+  std::vector<Control*> child_vector_;
+  Control*& child_;
+};
+}  // namespace cru::ui
diff --git a/src/ui/control.cpp b/src/ui/control.cpp
index 98986d3c..e19754dc 100644
--- a/src/ui/control.cpp
+++ b/src/ui/control.cpp
@@ -35,14 +35,14 @@ void Control::_SetDescendantWindow(Window* window) {
 
 void Control::TraverseDescendants(
     const std::function<void(Control*)>& predicate) {
-  TraverseDescendantsInternal(this, predicate);
+  _TraverseDescendants(this, predicate);
 }
 
-void Control::TraverseDescendantsInternal(
+void Control::_TraverseDescendants(
     Control* control, const std::function<void(Control*)>& predicate) {
   predicate(control);
   for (auto c : control->GetChildren())
-    TraverseDescendantsInternal(c, predicate);
+    _TraverseDescendants(c, predicate);
 }
 bool Control::RequestFocus() {
   auto window = GetWindow();
@@ -76,108 +76,4 @@ void Control::OnDetachToWindow(Window* window) {}
 void Control::OnMouseClickBegin(MouseButton button) {}
 
 void Control::OnMouseClickEnd(MouseButton button) {}
-
-const std::vector<Control*> NoChildControl::empty_control_vector{};
-
-ContentControl::ContentControl()
-    : child_vector_{nullptr}, child_(child_vector_[0]) {}
-
-ContentControl::~ContentControl() { delete child_; }
-
-void ContentControl::SetChild(Control* child) {
-  if (child == child_) return;
-
-  const auto window = GetWindow();
-  const auto old_child = child_;
-  child_ = child;
-  if (old_child) {
-    old_child->_SetParent(nullptr);
-    old_child->_SetDescendantWindow(nullptr);
-  }
-  if (child) {
-    child->_SetParent(this);
-    child->_SetDescendantWindow(window);
-  }
-  OnChildChanged(old_child, child);
-}
-
-void ContentControl::OnChildChanged(Control* old_child, Control* new_child) {}
-
-void ControlAddChildCheck(Control* control) {
-  if (control->GetParent() != nullptr)
-    throw std::invalid_argument("The control already has a parent.");
-
-  if (dynamic_cast<Window*>(control))
-    throw std::invalid_argument("Can't add a window as child.");
-}
-
-Layout::~Layout() {
-  for (const auto child : children_) delete child;
-}
-
-void Layout::AddChild(Control* control, const int position) {
-  ControlAddChildCheck(control);
-
-  if (position < 0 || static_cast<decltype(children_.size())>(position) >
-                          this->children_.size())
-    throw std::invalid_argument("The position is out of range.");
-
-  children_.insert(this->children_.cbegin() + position, control);
-
-  control->_SetParent(this);
-  control->_SetDescendantWindow(GetWindow());
-
-  OnAddChild(control, position);
-}
-
-void Layout::RemoveChild(const int position) {
-  if (position < 0 || static_cast<decltype(this->children_.size())>(position) >=
-                          this->children_.size())
-    throw std::invalid_argument("The position is out of range.");
-
-  const auto i = children_.cbegin() + position;
-  const auto child = *i;
-
-  children_.erase(i);
-
-  child->_SetParent(nullptr);
-  child->_SetDescendantWindow(nullptr);
-
-  OnRemoveChild(child, position);
-}
-
-void Layout::OnAddChild(Control* child, int position) {}
-
-void Layout::OnRemoveChild(Control* child, int position) {}
-
-std::list<Control*> GetAncestorList(Control* control) {
-  std::list<Control*> l;
-  while (control != nullptr) {
-    l.push_front(control);
-    control = control->GetParent();
-  }
-  return l;
-}
-
-Control* FindLowestCommonAncestor(Control* left, Control* right) {
-  if (left == nullptr || right == nullptr) return nullptr;
-
-  auto&& left_list = GetAncestorList(left);
-  auto&& right_list = GetAncestorList(right);
-
-  // the root is different
-  if (left_list.front() != right_list.front()) return nullptr;
-
-  // find the last same control or the last control (one is ancestor of the
-  // other)
-  auto left_i = left_list.cbegin();
-  auto right_i = right_list.cbegin();
-  while (true) {
-    if (left_i == left_list.cend()) return *(--left_i);
-    if (right_i == right_list.cend()) return *(--right_i);
-    if (*left_i != *right_i) return *(--left_i);
-    ++left_i;
-    ++right_i;
-  }
-}
 }  // namespace cru::ui
diff --git a/src/ui/control.hpp b/src/ui/control.hpp
index 9ff407b0..8454e981 100644
--- a/src/ui/control.hpp
+++ b/src/ui/control.hpp
@@ -48,7 +48,7 @@ class Control : public Object {
   void _SetDescendantWindow(Window* window);
 
  private:
-  static void TraverseDescendantsInternal(
+  static void _TraverseDescendants(
       Control* control, const std::function<void(Control*)>& predicate);
 
  public:
@@ -110,138 +110,4 @@ class Control : public Object {
 
   Cursor::Ptr cursor_{};
 };
-
-class NoChildControl : public Control {
- private:
-  static const std::vector<Control*> empty_control_vector;
-
- protected:
-  NoChildControl() = default;
-
- public:
-  NoChildControl(const NoChildControl& other) = delete;
-  NoChildControl(NoChildControl&& other) = delete;
-  NoChildControl& operator=(const NoChildControl& other) = delete;
-  NoChildControl& operator=(NoChildControl&& other) = delete;
-  ~NoChildControl() override = default;
-
- protected:
-  const std::vector<Control*>& GetChildren() const override final {
-    return empty_control_vector;
-  }
-};
-
-class ContentControl : public Control {
- protected:
-  ContentControl();
-
- public:
-  ContentControl(const ContentControl& other) = delete;
-  ContentControl(ContentControl&& other) = delete;
-  ContentControl& operator=(const ContentControl& other) = delete;
-  ContentControl& operator=(ContentControl&& other) = delete;
-  ~ContentControl() override;
-
-  const std::vector<Control*>& GetChildren() const override final {
-    return child_vector_;
-  }
-  Control* GetChild() const { return child_; }
-  void SetChild(Control* child);
-
- protected:
-  virtual void OnChildChanged(Control* old_child, Control* new_child);
-
- private:
-  std::vector<Control*> child_vector_;
-  Control*& child_;
-};
-
-class Layout : public Control {
- protected:
-  Layout() = default;
-
- public:
-  Layout(const Layout& other) = delete;
-  Layout(Layout&& other) = delete;
-  Layout& operator=(const Layout& other) = delete;
-  Layout& operator=(Layout&& other) = delete;
-  ~Layout() override;
-
-  const std::vector<Control*>& GetChildren() const override final {
-    return children_;
-  }
-
-  void AddChild(Control* control, int position);
-
-  void RemoveChild(int position);
-
- protected:
-  virtual void OnAddChild(Control* child, int position);
-  virtual void OnRemoveChild(Control* child, int position);
-
- private:
-  std::vector<Control*> children_;
-};
-
-//*************** region: event dispatcher helper ***************
-
-// Dispatch the event.
-//
-// This will raise routed event of the control and its parent and parent's
-// parent ... (until "last_receiver" if it's not nullptr) with appropriate args.
-//
-// First tunnel from top to bottom possibly stopped by "handled" flag in
-// EventArgs. Second bubble from bottom to top possibly stopped by "handled"
-// flag in EventArgs. Last direct to each control.
-//
-// Args is of type "EventArgs". The first init argument is "sender", which is
-// automatically bound to each receiving control. The second init argument is
-// "original_sender", which is unchanged. And "args" will be perfectly forwarded
-// as the rest arguments.
-template <typename EventArgs, typename... Args>
-void DispatchEvent(Control* const original_sender,
-                   events::RoutedEvent<EventArgs> Control::*event_ptr,
-                   Control* const last_receiver, Args&&... args) {
-  std::list<Control*> receive_list;
-
-  auto parent = original_sender;
-  while (parent != last_receiver) {
-    receive_list.push_back(parent);
-    parent = parent->GetParent();
-  }
-
-  auto handled = false;
-
-  // tunnel
-  for (auto i = receive_list.crbegin(); i != receive_list.crend(); ++i) {
-    EventArgs event_args(*i, original_sender, std::forward<Args>(args)...);
-    (*i->*event_ptr).tunnel.Raise(event_args);
-    if (event_args.IsHandled()) {
-      handled = true;
-      break;
-    }
-  }
-
-  // bubble
-  if (!handled) {
-    for (auto i : receive_list) {
-      EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
-      (i->*event_ptr).bubble.Raise(event_args);
-      if (event_args.IsHandled()) break;
-    }
-  }
-
-  // direct
-  for (auto i : receive_list) {
-    EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
-    (i->*event_ptr).direct.Raise(event_args);
-  }
-}
-
-//*************** region: tree helper ***************
-
-// Find the lowest common ancestor.
-// Return nullptr if "left" and "right" are not in the same tree.
-Control* FindLowestCommonAncestor(Control* left, Control* right);
-
 }  // namespace cru::ui
diff --git a/src/ui/controls/flex_layout.hpp b/src/ui/controls/flex_layout.hpp
index 682ed8dc..2ab3e259 100644
--- a/src/ui/controls/flex_layout.hpp
+++ b/src/ui/controls/flex_layout.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #include "pre.hpp"
 
-#include "ui/control.hpp"
+#include "ui/layout_control.hpp"
 
 namespace cru::ui::render {
 class FlexLayoutRenderObject;
@@ -9,7 +9,7 @@ class FlexLayoutRenderObject;
 
 namespace cru::ui::controls {
 
-class FlexLayout : public Layout {
+class FlexLayout : public LayoutControl {
  public:
   static constexpr auto control_type = L"FlexLayout";
 
diff --git a/src/ui/controls/text_block.hpp b/src/ui/controls/text_block.hpp
index c345c5ab..4c443020 100644
--- a/src/ui/controls/text_block.hpp
+++ b/src/ui/controls/text_block.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #include "pre.hpp"
 
-#include "ui/control.hpp"
+#include "ui/no_child_control.hpp"
 
 namespace cru::ui::render {
 class TextRenderObject;
diff --git a/src/ui/layout_control.cpp b/src/ui/layout_control.cpp
new file mode 100644
index 00000000..d2b430dd
--- /dev/null
+++ b/src/ui/layout_control.cpp
@@ -0,0 +1,52 @@
+#include "layout_control.hpp"
+
+#include "window.hpp"
+
+namespace cru::ui {
+void ControlAddChildCheck(Control* control) {
+  if (control->GetParent() != nullptr)
+    throw std::invalid_argument("The control already has a parent.");
+
+  if (dynamic_cast<Window*>(control))
+    throw std::invalid_argument("Can't add a window as child.");
+}
+
+LayoutControl::~LayoutControl() {
+  for (const auto child : children_) delete child;
+}
+
+void LayoutControl::AddChild(Control* control, const int position) {
+  ControlAddChildCheck(control);
+
+  if (position < 0 || static_cast<decltype(children_.size())>(position) >
+                          this->children_.size())
+    throw std::invalid_argument("The position is out of range.");
+
+  children_.insert(this->children_.cbegin() + position, control);
+
+  control->_SetParent(this);
+  control->_SetDescendantWindow(GetWindow());
+
+  OnAddChild(control, position);
+}
+
+void LayoutControl::RemoveChild(const int position) {
+  if (position < 0 || static_cast<decltype(this->children_.size())>(position) >=
+                          this->children_.size())
+    throw std::invalid_argument("The position is out of range.");
+
+  const auto i = children_.cbegin() + position;
+  const auto child = *i;
+
+  children_.erase(i);
+
+  child->_SetParent(nullptr);
+  child->_SetDescendantWindow(nullptr);
+
+  OnRemoveChild(child, position);
+}
+
+void LayoutControl::OnAddChild(Control* child, int position) {}
+
+void LayoutControl::OnRemoveChild(Control* child, int position) {}
+}  // namespace cru::ui
diff --git a/src/ui/layout_control.hpp b/src/ui/layout_control.hpp
new file mode 100644
index 00000000..53f53186
--- /dev/null
+++ b/src/ui/layout_control.hpp
@@ -0,0 +1,33 @@
+#pragma once
+#include "pre.hpp"
+
+#include "control.hpp"
+
+namespace cru::ui {
+class LayoutControl : public Control {
+ protected:
+  LayoutControl() = default;
+
+ public:
+  LayoutControl(const LayoutControl& other) = delete;
+  LayoutControl(LayoutControl&& other) = delete;
+  LayoutControl& operator=(const LayoutControl& other) = delete;
+  LayoutControl& operator=(LayoutControl&& other) = delete;
+  ~LayoutControl() override;
+
+  const std::vector<Control*>& GetChildren() const override final {
+    return children_;
+  }
+
+  void AddChild(Control* control, int position);
+
+  void RemoveChild(int position);
+
+ protected:
+  virtual void OnAddChild(Control* child, int position);
+  virtual void OnRemoveChild(Control* child, int position);
+
+ private:
+  std::vector<Control*> children_;
+};
+}  // namespace cru::ui
diff --git a/src/ui/no_child_control.cpp b/src/ui/no_child_control.cpp
new file mode 100644
index 00000000..e6bbe813
--- /dev/null
+++ b/src/ui/no_child_control.cpp
@@ -0,0 +1,5 @@
+#include "no_child_control.hpp"
+
+namespace cru::ui {
+const std::vector<Control*> NoChildControl::empty_control_vector{};
+}
diff --git a/src/ui/no_child_control.hpp b/src/ui/no_child_control.hpp
new file mode 100644
index 00000000..26b5546f
--- /dev/null
+++ b/src/ui/no_child_control.hpp
@@ -0,0 +1,26 @@
+#pragma once
+#include "pre.hpp"
+
+#include "control.hpp"
+
+namespace cru::ui {
+class NoChildControl : public Control {
+ private:
+  static const std::vector<Control*> empty_control_vector;
+
+ protected:
+  NoChildControl() = default;
+
+ public:
+  NoChildControl(const NoChildControl& other) = delete;
+  NoChildControl(NoChildControl&& other) = delete;
+  NoChildControl& operator=(const NoChildControl& other) = delete;
+  NoChildControl& operator=(NoChildControl&& other) = delete;
+  ~NoChildControl() override = default;
+
+ protected:
+  const std::vector<Control*>& GetChildren() const override final {
+    return empty_control_vector;
+  }
+};
+}  // namespace cru::ui
diff --git a/src/ui/window.cpp b/src/ui/window.cpp
index f92811a7..b976ca6a 100644
--- a/src/ui/window.cpp
+++ b/src/ui/window.cpp
@@ -7,6 +7,92 @@
 #include "render/window_render_object.hpp"
 
 namespace cru::ui {
+namespace {
+// Dispatch the event.
+//
+// This will raise routed event of the control and its parent and parent's
+// parent ... (until "last_receiver" if it's not nullptr) with appropriate args.
+//
+// First tunnel from top to bottom possibly stopped by "handled" flag in
+// EventArgs. Second bubble from bottom to top possibly stopped by "handled"
+// flag in EventArgs. Last direct to each control.
+//
+// Args is of type "EventArgs". The first init argument is "sender", which is
+// automatically bound to each receiving control. The second init argument is
+// "original_sender", which is unchanged. And "args" will be perfectly forwarded
+// as the rest arguments.
+template <typename EventArgs, typename... Args>
+void DispatchEvent(Control* const original_sender,
+                   events::RoutedEvent<EventArgs> Control::*event_ptr,
+                   Control* const last_receiver, Args&&... args) {
+  std::list<Control*> receive_list;
+
+  auto parent = original_sender;
+  while (parent != last_receiver) {
+    receive_list.push_back(parent);
+    parent = parent->GetParent();
+  }
+
+  auto handled = false;
+
+  // tunnel
+  for (auto i = receive_list.crbegin(); i != receive_list.crend(); ++i) {
+    EventArgs event_args(*i, original_sender, std::forward<Args>(args)...);
+    (*i->*event_ptr).tunnel.Raise(event_args);
+    if (event_args.IsHandled()) {
+      handled = true;
+      break;
+    }
+  }
+
+  // bubble
+  if (!handled) {
+    for (auto i : receive_list) {
+      EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
+      (i->*event_ptr).bubble.Raise(event_args);
+      if (event_args.IsHandled()) break;
+    }
+  }
+
+  // direct
+  for (auto i : receive_list) {
+    EventArgs event_args(i, original_sender, std::forward<Args>(args)...);
+    (i->*event_ptr).direct.Raise(event_args);
+  }
+}
+
+std::list<Control*> GetAncestorList(Control* control) {
+  std::list<Control*> l;
+  while (control != nullptr) {
+    l.push_front(control);
+    control = control->GetParent();
+  }
+  return l;
+}
+
+Control* FindLowestCommonAncestor(Control* left, Control* right) {
+  if (left == nullptr || right == nullptr) return nullptr;
+
+  auto&& left_list = GetAncestorList(left);
+  auto&& right_list = GetAncestorList(right);
+
+  // the root is different
+  if (left_list.front() != right_list.front()) return nullptr;
+
+  // find the last same control or the last control (one is ancestor of the
+  // other)
+  auto left_i = left_list.cbegin();
+  auto right_i = right_list.cbegin();
+  while (true) {
+    if (left_i == left_list.cend()) return *(--left_i);
+    if (right_i == right_list.cend()) return *(--right_i);
+    if (*left_i != *right_i) return *(--left_i);
+    ++left_i;
+    ++right_i;
+  }
+}
+}  // namespace
+
 LRESULT __stdcall GeneralWndProc(HWND hWnd, UINT Msg, WPARAM wParam,
                                  LPARAM lParam) {
   auto window = WindowManager::GetInstance()->FromHandle(hWnd);
diff --git a/src/ui/window.hpp b/src/ui/window.hpp
index 7a28c257..3e0422b1 100644
--- a/src/ui/window.hpp
+++ b/src/ui/window.hpp
@@ -5,7 +5,7 @@
 #include <memory>
 #include "system_headers.hpp"
 
-#include "control.hpp"
+#include "content_control.hpp"
 #include "events/ui_event.hpp"
 #include "window_class.hpp"
 
@@ -230,13 +230,6 @@ class Window final : public ContentControl {
 
   bool window_focus_ = false;
   Control* focus_control_ = this;  // "focus_control_" can't be nullptr
-
   Control* mouse_capture_control_ = nullptr;
-
-  bool is_layout_invalid_ = false;
-
-#ifdef CRU_DEBUG_LAYOUT
-  bool debug_layout_ = false;
-#endif
 };
 }  // namespace cru::ui
diff --git a/src/util/format.hpp b/src/util/format.hpp
index 874c5b43..7c1cee05 100644
--- a/src/util/format.hpp
+++ b/src/util/format.hpp
@@ -5,26 +5,29 @@
 
 namespace cru::util {
 namespace details {
-constexpr StringView PlaceHolder(type_tag<String>) { return StringView(L"{}"); }
+template <typename T>
+struct TypeTag {};
 
-constexpr MultiByteStringView PlaceHolder(type_tag<MultiByteString>) {
+constexpr StringView PlaceHolder(TypeTag<String>) { return StringView(L"{}"); }
+
+constexpr MultiByteStringView PlaceHolder(TypeTag<MultiByteString>) {
   return MultiByteStringView("{}");
 }
 
 template <typename TString>
 void FormatInternal(TString& string) {
-  const auto find_result = string.find(PlaceHolder(type_tag<TString>{}));
+  const auto find_result = string.find(PlaceHolder(TypeTag<TString>{}));
   if (find_result != TString::npos)
     throw std::invalid_argument("There is more placeholders than args.");
 }
 
 template <typename TString, typename T, typename... TRest>
 void FormatInternal(TString& string, const T& arg, const TRest&... args) {
-  const auto find_result = string.find(PlaceHolder(type_tag<TString>{}));
+  const auto find_result = string.find(PlaceHolder(TypeTag<TString>{}));
   if (find_result == TString::npos)
     throw std::invalid_argument("There is less placeholders than args.");
 
-  string.replace(find_result, 2, FormatToString(arg, type_tag<TString>{}));
+  string.replace(find_result, 2, FormatToString(arg, TypeTag<TString>{}));
   FormatInternal<TString>(string, args...);
 }
 }  // namespace details
@@ -43,13 +46,13 @@ MultiByteString Format(const MultiByteStringView& format, const T&... args) {
   return result;
 }
 
-#define CRU_FORMAT_NUMBER(type)                                       \
-  inline String FormatToString(const type number, type_tag<String>) { \
-    return std::to_wstring(number);                                   \
-  }                                                                   \
-  inline MultiByteString FormatToString(const type number,            \
-                                        type_tag<MultiByteString>) {  \
-    return std::to_string(number);                                    \
+#define CRU_FORMAT_NUMBER(type)                                               \
+  inline String FormatToString(const type number, details::TypeTag<String>) { \
+    return std::to_wstring(number);                                           \
+  }                                                                           \
+  inline MultiByteString FormatToString(const type number,                    \
+                                        details::TypeTag<MultiByteString>) {  \
+    return std::to_string(number);                                            \
   }
 
 CRU_FORMAT_NUMBER(int)
@@ -65,30 +68,33 @@ CRU_FORMAT_NUMBER(double)
 
 #undef CRU_FORMAT_NUMBER
 
-inline StringView FormatToString(const String& string, type_tag<String>) {
+inline StringView FormatToString(const String& string,
+                                 details::TypeTag<String>) {
   return string;
 }
 
 inline MultiByteString FormatToString(const MultiByteString& string,
-                                      type_tag<MultiByteString>) {
+                                      details::TypeTag<MultiByteString>) {
   return string;
 }
 
-inline StringView FormatToString(const StringView& string, type_tag<String>) {
+inline StringView FormatToString(const StringView& string,
+                                 details::TypeTag<String>) {
   return string;
 }
 
 inline MultiByteStringView FormatToString(const MultiByteStringView& string,
-                                          type_tag<MultiByteString>) {
+                                          details::TypeTag<MultiByteString>) {
   return string;
 }
 
-inline StringView FormatToString(const wchar_t* string, type_tag<String>) {
+inline StringView FormatToString(const wchar_t* string,
+                                 details::TypeTag<String>) {
   return StringView(string);
 }
 
 inline MultiByteStringView FormatToString(const char* string,
-                                          type_tag<MultiByteString>) {
+                                          details::TypeTag<MultiByteString>) {
   return MultiByteString(string);
 }
 }  // namespace cru::util