Introduce Options and use them for Menu.

Introduce Options for components. This allows me to add new features,
without updating functions signatures.

examples/component/menu.cpp

@@ -19,8 +19,9 @@ int main(int argc, const char* argv[]) {
   };
   int selected = 0;
 
-  auto menu = Menu(&entries, &selected);
-  MenuBase::From(menu)->on_enter = screen.ExitLoopClosure();
+  MenuOption option;
+  option.on_enter = screen.ExitLoopClosure();
+  auto menu = Menu(&entries, &selected, &option);
 
   screen.Loop(menu);
 

examples/component/menu2.cpp

@@ -13,6 +13,7 @@
 
 int main(int argc, const char* argv[]) {
   using namespace ftxui;
+  auto screen = ScreenInteractive::TerminalOutput();
 
   std::vector<std::wstring> left_menu_entries = {
       L"0%",  L"10%", L"20%", L"30%", L"40%",
@@ -22,10 +23,16 @@ int main(int argc, const char* argv[]) {
       L"0%", L"1%", L"2%", L"3%", L"4%",  L"5%",
       L"6%", L"7%", L"8%", L"9%", L"10%",
   };
+
+  auto menu_option = MenuOption();
+  menu_option.on_enter = screen.ExitLoopClosure();
+
   int left_menu_selected = 0;
   int right_menu_selected = 0;
-  Component left_menu_ = Menu(&left_menu_entries, &left_menu_selected);
-  Component right_menu_ = Menu(&right_menu_entries, &right_menu_selected);
+  Component left_menu_ =
+      Menu(&left_menu_entries, &left_menu_selected, &menu_option);
+  Component right_menu_ =
+      Menu(&right_menu_entries, &right_menu_selected, &menu_option);
 
   Component container = Container::Horizontal({
       left_menu_,
@@ -68,9 +75,6 @@ int main(int argc, const char* argv[]) {
            border;
   });
 
-  auto screen = ScreenInteractive::TerminalOutput();
-  MenuBase::From(left_menu_)->on_enter = screen.ExitLoopClosure();
-  MenuBase::From(right_menu_)->on_enter = screen.ExitLoopClosure();
   screen.Loop(renderer);
 }
 

examples/component/menu_style.cpp

@@ -14,6 +14,8 @@
 
 int main(int argc, const char* argv[]) {
   using namespace ftxui;
+  auto screen = ScreenInteractive::TerminalOutput();
+
   std::vector<std::wstring> entries = {
       L"Monkey", L"Dog", L"Cat", L"Bird", L"Elephant",
   };
@@ -23,12 +25,51 @@ int main(int argc, const char* argv[]) {
   int menu_4_selected_ = 0;
   int menu_5_selected_ = 0;
   int menu_6_selected_ = 0;
-  auto menu_1_ = Menu(&entries, &menu_1_selected_);
-  auto menu_2_ = Menu(&entries, &menu_2_selected_);
-  auto menu_3_ = Menu(&entries, &menu_3_selected_);
-  auto menu_4_ = Menu(&entries, &menu_4_selected_);
-  auto menu_5_ = Menu(&entries, &menu_5_selected_);
-  auto menu_6_ = Menu(&entries, &menu_6_selected_);
+
+  MenuOption option_1;
+  option_1.focused_style = bold | color(Color::Blue);
+  option_1.selected_style = color(Color::Blue);
+  option_1.selected_focused_style = bold | color(Color::Blue);
+  option_1.on_enter = screen.ExitLoopClosure();
+  auto menu_1_ = Menu(&entries, &menu_1_selected_, &option_1);
+
+  MenuOption option_2;
+  option_2.focused_style = bold | color(Color::Blue);
+  option_2.selected_style = color(Color::Blue);
+  option_2.selected_focused_style = bold | color(Color::Blue);
+  option_2.on_enter = screen.ExitLoopClosure();
+  auto menu_2_ = Menu(&entries, &menu_2_selected_, &option_2);
+
+  MenuOption option_3;
+  option_3.selected_style = color(Color::Blue);
+  option_3.focused_style = bgcolor(Color::Blue);
+  option_3.selected_focused_style = bgcolor(Color::Blue);
+  option_3.on_enter = screen.ExitLoopClosure();
+  auto menu_3_ = Menu(&entries, &menu_3_selected_, &option_3);
+
+  MenuOption option_4;
+  option_4.selected_style = bgcolor(Color::Blue);
+  option_4.focused_style = bgcolor(Color::BlueLight);
+  option_4.selected_focused_style = bgcolor(Color::BlueLight);
+  option_4.on_enter = screen.ExitLoopClosure();
+  auto menu_4_ = Menu(&entries, &menu_4_selected_, &option_4);
+
+  MenuOption option_5;
+  option_5.normal_style = bgcolor(Color::Blue);
+  option_5.selected_style = bgcolor(Color::Yellow);
+  option_5.focused_style = bgcolor(Color::Red);
+  option_5.selected_focused_style = bgcolor(Color::Red);
+  option_5.on_enter = screen.ExitLoopClosure();
+  auto menu_5_ = Menu(&entries, &menu_5_selected_, &option_5);
+
+  MenuOption option_6;
+  option_6.normal_style = dim | color(Color::Blue);
+  option_6.selected_style = color(Color::Blue);
+  option_6.focused_style = bold | color(Color::Blue);
+  option_6.selected_focused_style = bold | color(Color::Blue);
+  option_6.on_enter = screen.ExitLoopClosure();
+  auto menu_6_ = Menu(&entries, &menu_6_selected_, &option_6);
+
   auto container = Container::Horizontal({
       menu_1_,
       menu_2_,
@@ -51,31 +92,6 @@ int main(int argc, const char* argv[]) {
       }) | border;
   });
   // clang-format on
-  auto screen = ScreenInteractive::TerminalOutput();
-  for (Component menu : {menu_1_, menu_2_, menu_3_, menu_4_, menu_5_, menu_6_})
-    MenuBase::From(menu)->on_enter = screen.ExitLoopClosure();
-
-  MenuBase::From(menu_2_)->focused_style = bold | color(Color::Blue);
-  MenuBase::From(menu_2_)->selected_style = color(Color::Blue);
-  MenuBase::From(menu_2_)->selected_focused_style = bold | color(Color::Blue);
-
-  MenuBase::From(menu_3_)->selected_style = color(Color::Blue);
-  MenuBase::From(menu_3_)->focused_style = bgcolor(Color::Blue);
-  MenuBase::From(menu_3_)->selected_focused_style = bgcolor(Color::Blue);
-
-  MenuBase::From(menu_4_)->selected_style = bgcolor(Color::Blue);
-  MenuBase::From(menu_4_)->focused_style = bgcolor(Color::BlueLight);
-  MenuBase::From(menu_4_)->selected_focused_style = bgcolor(Color::BlueLight);
-
-  MenuBase::From(menu_5_)->normal_style = bgcolor(Color::Blue);
-  MenuBase::From(menu_5_)->selected_style = bgcolor(Color::Yellow);
-  MenuBase::From(menu_5_)->focused_style = bgcolor(Color::Red);
-  MenuBase::From(menu_5_)->selected_focused_style = bgcolor(Color::Red);
-
-  MenuBase::From(menu_6_)->normal_style = dim | color(Color::Blue);
-  MenuBase::From(menu_6_)->selected_style = color(Color::Blue);
-  MenuBase::From(menu_6_)->focused_style = bold | color(Color::Blue);
-  MenuBase::From(menu_6_)->selected_focused_style = bold | color(Color::Blue);
 
   screen.Loop(renderer);
 }

include/ftxui/component/component.hpp

@@ -7,8 +7,9 @@
 #include <vector>      // for vector
 
 #include "ftxui/component/component_base.hpp"
+#include "ftxui/component/component_options.hpp"
 #include "ftxui/dom/elements.hpp"   // for Element
-#include "ftxui/screen/string.hpp"  // for ConstStringRef, StringRef
+#include "ftxui/util/ref.hpp"       // for ConstStringRef, StringRef
 
 namespace ftxui {
 
@@ -28,7 +29,9 @@ Component Button(ConstStringRef label,
                  bool border = true);
 Component Checkbox(ConstStringRef label, bool* checked);
 Component Input(StringRef content, ConstStringRef placeholder);
-Component Menu(const std::vector<std::wstring>* entries, int* selected_);
+Component Menu(const std::vector<std::wstring>* entries,
+               int* selected_,
+               ConstRef<MenuOption> = {});
 Component Radiobox(const std::vector<std::wstring>* entries, int* selected_);
 Component Toggle(const std::vector<std::wstring>* entries, int* selected);
 template <class T>  // T = {int, float, long}

include/ftxui/component/component_options.hpp

@@ -0,0 +1,19 @@
+#ifndef FTXUI_COMPONENT_COMPONENT_OPTIONS_HPP
+#define FTXUI_COMPONENT_COMPONENT_OPTIONS_HPP
+
+namespace ftxui {
+
+struct MenuOption {
+  Decorator normal_style = nothing;
+  Decorator focused_style = inverted;
+  Decorator selected_style = bold;
+  Decorator selected_focused_style = focused_style | selected_style;
+
+  // State update callback.
+  std::function<void()> on_change = []() {};
+  std::function<void()> on_enter = []() {};
+};
+
+};     // namespace ftxui
+
+#endif /* end of include guard: FTXUI_COMPONENT_COMPONENT_OPTIONS_HPP */

include/ftxui/component/menu.hpp

@@ -7,6 +7,7 @@
 
 #include "ftxui/component/component.hpp"          // for Component
 #include "ftxui/component/component_base.hpp"     // for ComponentBase
+#include "ftxui/component/component_options.hpp"  // for Component
 #include "ftxui/dom/elements.hpp"  // for Element, Decorator, operator|, bold, inverted, nothing
 #include "ftxui/screen/box.hpp"  // for Box
 
@@ -21,21 +22,14 @@ class MenuBase : public ComponentBase {
   static MenuBase* From(Component component);
 
   // Constructor.
-  MenuBase(const std::vector<std::wstring>* entries, int* selected_);
+  MenuBase(const std::vector<std::wstring>* entries,
+           int* selected_,
+           ConstRef<MenuOption> option = {});
   ~MenuBase() override = default;
 
   // State.
   int focused = 0;
 
-  Decorator normal_style = nothing;
-  Decorator focused_style = inverted;
-  Decorator selected_style = bold;
-  Decorator selected_focused_style = focused_style | selected_style;
-
-  // State update callback.
-  std::function<void()> on_change = []() {};
-  std::function<void()> on_enter = []() {};
-
   // Component implementation.
   Element Render() override;
   bool OnEvent(Event) override;
@@ -43,6 +37,7 @@ class MenuBase : public ComponentBase {
  protected:
   const std::vector<std::wstring>* const entries_;
   int* selected_ = 0;
+  ConstRef<MenuOption> option_;
 
   bool OnMouseEvent(Event);
 

include/ftxui/screen/string.hpp

@@ -19,40 +19,6 @@ int wchar_width_cjk(wchar_t);
 int wstring_width(const std::wstring&);
 int wstring_width_cjk(const std::wstring&);
 
-/// @brief For convenience, this class convert multiple mutable string
-/// references toward a shared representation.
-class StringRef {
- public:
-  StringRef(std::wstring* ref);
-  StringRef(std::wstring ref);
-  StringRef(const wchar_t* ref);
-  StringRef(const char* ref);
-
-  std::wstring& operator*();
-  std::wstring* operator->();
-
- private:
-  std::wstring* const borrowed_ = nullptr;
-  std::wstring owned_;
-};
-
-/// @brief For convenience, this class convert multiple immutable string
-/// references toward  shared representation.
-class ConstStringRef {
- public:
-  ConstStringRef(const std::wstring* ref);
-  ConstStringRef(std::wstring ref);
-  ConstStringRef(const wchar_t* ref);
-  ConstStringRef(const char* ref);
-
-  const std::wstring& operator*();
-  const std::wstring* operator->();
-
- private:
-  const std::wstring* const borrowed_ = nullptr;
-  const std::wstring owned_;
-};
-
 }  // namespace ftxui
 
 #endif /* end of include guard: FTXUI_SCREEN_STRING_HPP */

include/ftxui/util/ref.hpp

@@ -0,0 +1,63 @@
+#ifndef FTXUI_UTIL_REF_HPP
+#define FTXUI_UTIL_REF_HPP
+
+#include <ftxui/screen/string.hpp>
+#include <string>
+
+namespace ftxui {
+
+// An adapter for a const object referenced or owned.
+template <typename T>
+class ConstRef {
+ public:
+  ConstRef() {}
+  ConstRef(T t): owned_(t) {}
+  ConstRef(const T* t) : address_(t) {}
+  const T& operator*() { return address_ ? *address_ : owned_; }
+  const T* operator->() { return address_ ? address_ : &owned_; }
+
+ private:
+  T owned_;
+  const T* address_ = nullptr;
+};
+
+/// @brief For convenience, this class convert multiple mutable string
+/// references toward a shared representation.
+class StringRef {
+ public:
+  StringRef(std::wstring* ref) : address_(ref) {}
+  StringRef(std::wstring ref) : owned_(std::move(ref)) {}
+  StringRef(const wchar_t* ref) : StringRef(std::wstring(ref)) {}
+  StringRef(const char* ref) : StringRef(to_wstring(std::string(ref))) {}
+  std::wstring& operator*() { return address_ ? *address_ : owned_; }
+  std::wstring* operator->() { return address_ ? address_ : &owned_; }
+
+ private:
+  std::wstring owned_;
+  std::wstring* address_ = nullptr;
+};
+
+/// @brief For convenience, this class convert multiple immutable string
+/// references toward  shared representation.
+class ConstStringRef {
+ public:
+  ConstStringRef(const std::wstring* ref) : address_(ref) {}
+  ConstStringRef(std::wstring ref) : owned_(std::move(ref)) {}
+  ConstStringRef(const wchar_t* ref) : ConstStringRef(std::wstring(ref)) {}
+  ConstStringRef(const char* ref)
+      : ConstStringRef(to_wstring(std::string(ref))) {}
+  const std::wstring& operator*() { return address_ ? *address_ : owned_; }
+  const std::wstring* operator->() { return address_ ? address_ : &owned_; }
+
+ private:
+  const std::wstring owned_;
+  const std::wstring* address_ = nullptr;
+};
+
+}  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_UTIL_REF_HPP */
+
+// Copyright 2020 Arthur Sonzogni. All rights reserved.
+// Use of this source code is governed by the MIT license that can be found in
+// the LICENSE file.

src/ftxui/component/menu.cpp

@@ -38,8 +38,10 @@ namespace ftxui {
 ///   entry 2
 ///   entry 3
 /// ```
-Component Menu(const std::vector<std::wstring>* entries, int* selected) {
-  return Make<MenuBase>(entries, selected);
+Component Menu(const std::vector<std::wstring>* entries,
+               int* selected,
+               ConstRef<MenuOption> option) {
+  return Make<MenuBase>(entries, selected, std::move(option));
 }
 
 // static
@@ -47,8 +49,10 @@ MenuBase* MenuBase::From(Component component) {
   return static_cast<MenuBase*>(component.get());
 }
 
-MenuBase::MenuBase(const std::vector<std::wstring>* entries, int* selected)
-    : entries_(entries), selected_(selected) {}
+MenuBase::MenuBase(const std::vector<std::wstring>* entries,
+                   int* selected,
+                   ConstRef<MenuOption> option)
+    : entries_(entries), selected_(selected), option_(option) {}
 
 Element MenuBase::Render() {
   Elements elements;
@@ -58,9 +62,10 @@ Element MenuBase::Render() {
     bool is_focused = (focused == int(i)) && is_menu_focused;
     bool is_selected = (*selected_ == int(i));
 
-    auto style = is_selected
-                     ? (is_focused ? selected_focused_style : selected_style)
-                     : (is_focused ? focused_style : normal_style);
+    auto style = is_selected ? (is_focused ? option_->selected_focused_style
+                                           : option_->selected_style)
+                             : (is_focused ? option_->focused_style
+                                           : option_->normal_style);
     auto focus_management = !is_selected      ? nothing
                             : is_menu_focused ? focus
                                               : select;
@@ -94,12 +99,12 @@ bool MenuBase::OnEvent(Event event) {
 
   if (*selected_ != old_selected) {
     focused = *selected_;
-    on_change();
+    option_->on_change();
     return true;
   }
 
   if (event == Event::Return) {
-    on_enter();
+    option_->on_enter();
     return true;
   }
 
@@ -119,7 +124,7 @@ bool MenuBase::OnMouseEvent(Event event) {
         event.mouse().motion == Mouse::Released) {
       if (*selected_ != i) {
         *selected_ = i;
-        on_change();
+        option_->on_change();
       }
       return true;
     }

src/ftxui/screen/string.cpp

@@ -26,30 +26,6 @@ std::wstring to_wstring(const std::string& s) {
 #pragma warning(pop)
 #endif
 
-StringRef::StringRef(std::wstring* ref) : borrowed_(ref) {}
-StringRef::StringRef(std::wstring ref) : owned_(std::move(ref)) {}
-StringRef::StringRef(const wchar_t* ref) : owned_(ref) {}
-StringRef::StringRef(const char* ref) : owned_(to_wstring(std::string(ref))) {}
-std::wstring& StringRef::operator*() {
-  return borrowed_ ? *borrowed_ : owned_;
-}
-std::wstring* StringRef::operator->() {
-  return borrowed_ ? borrowed_ : &owned_;
-}
-
-ConstStringRef::ConstStringRef(const std::wstring* ref) : borrowed_(ref) {}
-ConstStringRef::ConstStringRef(std::wstring ref) : owned_(std::move(ref)) {}
-ConstStringRef::ConstStringRef(const wchar_t* ref) : owned_(ref) {}
-ConstStringRef::ConstStringRef(const char* ref)
-    : owned_(to_wstring(std::string(ref))) {}
-
-const std::wstring& ConstStringRef::operator*() {
-  return borrowed_ ? *borrowed_ : owned_;
-}
-const std::wstring* ConstStringRef::operator->() {
-  return borrowed_ ? borrowed_ : &owned_;
-}
-
 }  // namespace ftxui
 
 // Copyright 2020 Arthur Sonzogni. All rights reserved.