Add the Button component.

include/ftxui/component/button.hpp

@@ -0,0 +1,36 @@
+#ifndef FTXUI_COMPONENT_BUTTON_HPP
+#define FTXUI_COMPONENT_BUTTON_HPP
+
+#include <functional>
+
+#include "ftxui/component/component.hpp"
+
+namespace ftxui {
+
+/// @brief A button. An action is associated to the click event.
+/// @ingroup dom
+class Button : public Component {
+ public:
+  // Constructor.
+  Button() = default;
+  Button(std::wstring label) : label(label) {}
+  ~Button() override = default;
+
+  /// The Button label.
+  std::wstring label = L"button";
+
+  /// Called when the user press the "enter" button.
+  std::function<void()> on_click = [] {};
+
+  // Component implementation.
+  Element Render() override;
+  bool OnEvent(Event) override;
+};
+
+}  // namespace ftxui
+
+#endif /* end of include guard: FTXUI_COMPONENT_BUTTON_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.