Merge pull request #536 from MihailRis/selectbox

'select' ui element

src/coders/yaml.cpp

@@ -308,7 +308,7 @@ dv::value Parser::parseObject(dv::value&& object, int indent) {
         object[std::string(name)] = parseFullValue(indent);
         skipEmptyLines();
     }
-    return object;
+    return std::move(object);
 }
 
 dv::value yaml::parse(std::string_view filename, std::string_view source) {

src/graphics/core/Batch2D.cpp

@@ -333,6 +333,15 @@ void Batch2D::rect(
     vertex(v1, glm::vec2(0, 0), r2,g2,b2,1.0f);
 }
 
+void Batch2D::triangle(float x1, float y1, float x2, float y2, float x3, float y3) {
+    if (index + 3 >= capacity) {
+        flush();
+    }
+    vertex({x1, y1}, {x1, y1}, color.r, color.g, color.b, color.a);
+    vertex({x2, y2}, {x2, y2}, color.r, color.g, color.b, color.a);
+    vertex({x3, y3}, {x3, y3}, color.r, color.g, color.b, color.a);
+}
+
 void Batch2D::sprite(float x, float y, float w, float h, const UVRegion& region, glm::vec4 tint){
     rect(x, y, w, h, region.u1, region.v1, region.u2-region.u1, region.v2-region.v1, tint.r, tint.g, tint.b, tint.a);
 }

src/graphics/core/Batch2D.hpp

@@ -117,6 +117,8 @@ public:
         float r4, float g4, float b4, int sh
     );
 
+    void triangle(float x1, float y1, float x2, float y2, float x3, float y3);
+
     void flush() override;
 
     void lineWidth(float width);

src/graphics/ui/GUI.hpp

@@ -89,6 +89,8 @@ namespace gui {
         void updateTooltip(float delta);
         void resetTooltip();
     public:
+        static constexpr int CONTEXT_MENU_ZINDEX = 999;
+
         GUI(Engine& engine);
         ~GUI();
 

src/graphics/ui/elements/Button.cpp

@@ -34,14 +34,12 @@ Button::Button(
     const onaction& action,
     glm::vec2 size
 )
-    : Panel(gui, size, padding, 0) {
-    if (size.y < 0.0f) {
-        size = glm::vec2(
-            glm::max(padding.x + padding.z + text.length() * 8, size.x),
-            glm::max(padding.y + padding.w + 16, size.y)
-        );
+    : Panel(gui, size, padding, 0.0f) {
+    if (size.x < 0.0f || size.y < 0.0f) {
+        setContentSize({text.length() * 8, 16});
+    } else {
+        setSize(size);
     }
-    setSize(size);
 
     if (action) {
         listenAction(action);
@@ -50,13 +48,12 @@ Button::Button(
 
     label = std::make_shared<Label>(gui, text);
     label->setAlign(Align::center);
-    label->setSize(
-        size - glm::vec2(padding.z + padding.x, padding.w + padding.y)
-    );
+    label->setSize(getContentSize());
     label->setInteractive(false);
     add(label);
-    setHoverColor(glm::vec4(0.05f, 0.1f, 0.15f, 0.75f));
-    setPressedColor(glm::vec4(0.0f, 0.0f, 0.0f, 0.95f));
+    
+    setHoverColor({0.05f, 0.1f, 0.15f, 0.75f});
+    setPressedColor({0.0f, 0.0f, 0.0f, 0.95f});
 }
 
 void Button::setText(std::wstring text) {
@@ -72,19 +69,10 @@ std::wstring Button::getText() const {
     return L"";
 }
 
-Button* Button::textSupplier(wstringsupplier supplier) {
-    if (label) {
-        label->textSupplier(std::move(supplier));
-    }
-    return this;
-}
-
 void Button::refresh() {
     Panel::refresh();
     if (label) {
-        label->setSize(
-            size - glm::vec2(padding.z + padding.x, padding.w + padding.y)
-        );
+        label->setSize(getContentSize());
     }
 }
 

src/graphics/ui/elements/Button.hpp

@@ -33,8 +33,6 @@ namespace gui {
         virtual void setText(std::wstring text);
         virtual std::wstring getText() const;
 
-        virtual Button* textSupplier(wstringsupplier supplier);
-
         virtual void refresh() override;
     };
 }

src/graphics/ui/elements/Panel.cpp

@@ -27,6 +27,17 @@ int Panel::getMinLength() const {
     return minLength;
 }
 
+void Panel::setContentSize(const glm::ivec2& contentSize) {
+    setSize(glm::vec2(
+        glm::max(padding.x + padding.z + contentSize.x, size.x),
+        glm::max(padding.y + padding.w + contentSize.y, size.y)
+    ));
+}
+
+glm::vec2 Panel::getContentSize() const {
+    return size - glm::vec2(padding.z + padding.x, padding.w + padding.y);
+}
+
 void Panel::cropToContent() {
     if (maxLength > 0.0f) {
         setSize(glm::vec2(

src/graphics/ui/elements/Panel.hpp

@@ -27,6 +27,12 @@ namespace gui {
 
         virtual void setMinLength(int value);
         int getMinLength() const;
+
+        /// @brief .setSize wrapper automatically applying padding to size
+        /// @param size element size excluding padding
+        void setContentSize(const glm::ivec2& size);
+        /// @return element size excluding padding
+        glm::vec2 getContentSize() const;
     protected:
         int minLength = 0;
         int maxLength = 0;

src/graphics/ui/elements/SelectBox.cpp

@@ -0,0 +1,84 @@
+#include "SelectBox.hpp"
+
+#include "Label.hpp"
+#include "assets/Assets.hpp"
+#include "graphics/ui/GUI.hpp"
+#include "graphics/ui/elements/Panel.hpp"
+#include "graphics/core/Batch2D.hpp"
+#include "graphics/core/DrawContext.hpp"
+
+using namespace gui;
+
+SelectBox::SelectBox(
+    GUI& gui,
+    std::vector<Option>&& options,
+    Option selected,
+    int contentWidth,
+    const glm::vec4& padding
+)
+    : Button(gui, selected.text, padding, nullptr, glm::vec2(contentWidth, -1)),
+      options(std::move(options)) {
+
+    listenAction([this](GUI& gui) {
+        auto panel = std::make_shared<Panel>(gui, getSize());
+        panel->setPos(calcPos() + glm::vec2(0, size.y));
+        for (const auto& option : this->options) {
+            auto button = std::make_shared<Button>(
+                gui, option.text, glm::vec4(10.0f), nullptr, glm::vec2(-1.0f)
+            );
+            button->listenFocus([this, option](GUI& gui) {
+                setSelected(option);
+                changeCallbacks.notify(gui, option.value);
+            });
+            panel->add(button);
+        }
+        panel->setZIndex(GUI::CONTEXT_MENU_ZINDEX);
+        gui.setFocus(panel);
+        panel->listenDefocus([panel=panel.get()](GUI& gui) {
+            gui.remove(panel);
+        });
+        gui.add(panel);
+    });
+}
+
+void SelectBox::listenChange(onstringchange&& callback) {
+    changeCallbacks.listen(std::move(callback));
+}
+
+void SelectBox::setSelected(const Option& selected) {
+    this->selected = selected;
+    this->label->setText(selected.text);
+}
+
+const SelectBox::Option& SelectBox::getSelected() const {
+    return selected;
+}
+
+const std::vector<SelectBox::Option>& SelectBox::getOptions() const {
+    return options;
+}
+
+void SelectBox::setOptions(std::vector<Option>&& options) {
+    this->options = std::move(options);
+}
+
+void SelectBox::drawBackground(const DrawContext& pctx, const Assets&) {
+    glm::vec2 pos = calcPos();
+    auto batch = pctx.getBatch2D();
+    batch->untexture();
+    batch->setColor(calcColor());
+    batch->rect(pos.x, pos.y, size.x, size.y);
+    batch->setColor({1.0f, 1.0f, 1.0f, 0.333f});
+
+    int paddingRight = padding.w;
+    int widthHalf = 8;
+    int heightHalf = 4;
+    batch->triangle(
+        pos.x + size.x - paddingRight - widthHalf * 2,
+        pos.y + size.y / 2.0f - heightHalf,
+        pos.x + size.x - paddingRight,
+        pos.y + size.y / 2.0f - heightHalf,
+        pos.x + size.x - paddingRight - widthHalf,
+        pos.y + size.y / 2.0f + heightHalf
+    );
+}

src/graphics/ui/elements/SelectBox.hpp

@@ -0,0 +1,39 @@
+#pragma once
+
+#include "Button.hpp"
+
+namespace gui {
+    class Label;
+
+    class SelectBox : public Button {
+    public:
+        struct Option {
+            std::string value;
+            std::wstring text;
+        };
+    private:
+        std::vector<Option> options;
+        Option selected {};
+        StringCallbacksSet changeCallbacks;
+    public:
+        SelectBox(
+            GUI& gui,
+            std::vector<Option>&& elements,
+            Option selected,
+            int contentWidth,
+            const glm::vec4& padding
+        );
+
+        void listenChange(onstringchange&& callback);
+
+        void setSelected(const Option& selected);
+
+        const Option& getSelected() const;
+
+        const std::vector<Option>& getOptions() const;
+
+        void setOptions(std::vector<Option>&& options);
+
+        void drawBackground(const DrawContext& pctx, const Assets&) override;
+    };
+}

src/graphics/ui/elements/UINode.hpp

@@ -21,25 +21,33 @@ namespace gui {
 
     using onaction = std::function<void(GUI&)>;
     using onnumberchange = std::function<void(GUI&, double)>;
+    using onstringchange = std::function<void(GUI&, const std::string&)>;
 
-    class ActionsSet {
-        std::unique_ptr<std::vector<onaction>> callbacks;
+    template<typename... Args>
+    class CallbacksSet {
     public:
-        void listen(const onaction& callback) {
+        using Func = std::function<void(Args...)>;
+    private:
+        std::unique_ptr<std::vector<Func>> callbacks;
+    public:
+        void listen(const Func& callback) {
             if (callbacks == nullptr) {
-                callbacks = std::make_unique<std::vector<onaction>>();
+                callbacks = std::make_unique<std::vector<Func>>();
             }
             callbacks->push_back(callback);
         }
 
-        void notify(GUI& gui) {
+        void notify(Args&&... args) {
             if (callbacks) {
                 for (auto& callback : *callbacks) {
-                    callback(gui);
+                    callback(std::forward<Args>(args)...);
                 }
             }
         }
     };
+
+    using ActionsSet = CallbacksSet<GUI&>;
+    using StringCallbacksSet = CallbacksSet<GUI&, const std::string&>;
     
     enum class Align {
         left, center, right,

src/graphics/ui/gui_xml.cpp

@@ -11,6 +11,7 @@
 #include "elements/TextBox.hpp"
 #include "elements/SplitBox.hpp"
 #include "elements/TrackBar.hpp"
+#include "elements/SelectBox.hpp"
 #include "elements/Image.hpp"
 #include "elements/InlineFrame.hpp"
 #include "elements/InputBindBox.hpp"
@@ -30,7 +31,7 @@
 
 using namespace gui;
 
-static Align align_from_string(const std::string& str, Align def) {
+static Align align_from_string(std::string_view str, Align def) {
     if (str == "left") return Align::left;
     if (str == "center") return Align::center;
     if (str == "right") return Align::right;
@@ -151,7 +152,7 @@ static void read_uinode(
     if (element.has("pressed-color")) {
         node.setPressedColor(element.attr("pressed-color").asColor());
     }
-    std::string alignName = element.attr("align", "").getText();
+    const auto& alignName = element.attr("align", "").getText();
     node.setAlign(align_from_string(alignName, node.getAlign()));
 
     if (element.has("gravity")) {
@@ -287,8 +288,11 @@ static std::wstring parse_inner_text(
     const xml::xmlelement& element, const std::string& context
 ) {
     std::wstring text = L"";
-    if (element.size() == 1) {
-        std::string source = element.sub(0).getInnerText();
+    for (const auto& elem : element.getElements()) {
+        if (!elem->isText()) {
+            continue;
+        }
+        std::string source = elem->getInnerText();
         util::trim(source);
         text = util::str2wstr_utf8(source);
         if (text[0] == '@') {
@@ -298,6 +302,7 @@ static std::wstring parse_inner_text(
                 text = langs::get(text.substr(1), util::str2wstr_utf8(context));
             }
         }
+        break;
     }
     return text;
 }
@@ -426,6 +431,68 @@ static std::shared_ptr<UINode> read_button(
     return button;
 }
 
+static std::shared_ptr<UINode> read_select(
+    UiXmlReader& reader, const xml::xmlelement& element
+) {
+    auto& gui = reader.getGUI();
+    glm::vec4 padding = element.attr("padding", "10").asVec4();
+    int contentWidth = element.attr("width", "100").asInt();
+
+    auto& elements = element.getElements();
+    std::vector<SelectBox::Option> options;
+    SelectBox::Option selected;
+
+    for (const auto& elem : elements) {
+        const auto& tag = elem->getTag();
+        if (tag != "option") {
+            continue;
+        }
+        auto value = elem->attr("value").getText();
+        auto text = parse_inner_text(*elem, reader.getContext());
+        options.push_back(SelectBox::Option {std::move(value), std::move(text)});
+    }
+
+    if (element.has("selected")) {
+        auto selectedValue = element.attr("selected").getText();
+        selected.value = selectedValue;
+        selected.text = L"";
+        for (const auto& option : options) {
+            if (option.value == selectedValue) {
+                selected.text = option.text;
+            }
+        }
+        if (selected.text.empty()) {
+            selected.text = util::str2wstr_utf8(selected.value);
+        }
+    }
+
+    auto innerText = parse_inner_text(element, "");
+    if (!innerText.empty()) {
+        selected.text = innerText;
+    }
+
+    auto selectBox = std::make_shared<SelectBox>(
+        gui,
+        std::move(options),
+        std::move(selected),
+        contentWidth,
+        std::move(padding)
+    );
+    if (element.has("onselect")) {
+        auto callback = scripting::create_string_consumer(
+            reader.getEnvironment(),
+            element.attr("onselect").getText(),
+            reader.getFilename()
+        );
+        selectBox->listenChange(
+        [callback=std::move(callback)](GUI&, const std::string& value) {
+            callback(value);
+        });
+    }
+    read_panel_impl(reader, element, *selectBox, false);
+    return selectBox;
+}
+
 static std::shared_ptr<UINode> read_check_box(
     UiXmlReader& reader, const xml::xmlelement& element
 ) {
@@ -796,6 +863,7 @@ UiXmlReader::UiXmlReader(gui::GUI& gui, scriptenv&& env) : gui(gui), env(std::mo
     add("label", read_label);
     add("panel", read_panel);
     add("button", read_button);
+    add("select", read_select);
     add("textbox", read_text_box);
     add("pagebox", read_page_box);
     add("splitbox", read_split_box);

src/logic/scripting/lua/libs/libgui.cpp

@@ -8,6 +8,7 @@
 #include "graphics/ui/elements/Canvas.hpp"
 #include "graphics/ui/elements/CheckBox.hpp"
 #include "graphics/ui/elements/Image.hpp"
+#include "graphics/ui/elements/SelectBox.hpp"
 #include "graphics/ui/elements/InventoryView.hpp"
 #include "graphics/ui/elements/Menu.hpp"
 #include "graphics/ui/elements/Panel.hpp"
@@ -225,6 +226,8 @@ static int p_is_checked(UINode* node, lua::State* L) {
 static int p_get_value(UINode* node, lua::State* L) {
     if (auto bar = dynamic_cast<TrackBar*>(node)) {
         return lua::pushnumber(L, bar->getValue());
+    } else if (auto box = dynamic_cast<SelectBox*>(node)) {
+        return lua::pushstring(L, box->getSelected().value);
     }
     return 0;
 }
@@ -509,6 +512,28 @@ static int p_get_scroll(UINode* node, lua::State* L) {
     return 0;
 }
 
+static int p_get_options(UINode* node, lua::State* L) {
+    if (auto selectbox = dynamic_cast<SelectBox*>(node)) {
+        const auto& options = selectbox->getOptions();
+        size_t size = options.size();
+        lua::createtable(L, size, 0);
+        for (size_t i = 0; i < size; i++) {
+            const auto& option = options[i];
+            lua::createtable(L, 0, 2);
+
+            lua::pushstring(L, option.value);
+            lua::setfield(L, "value");
+
+            lua::pushwstring(L, option.text);
+            lua::setfield(L, "text");
+
+            lua::rawseti(L, i + 1);
+        }
+        return 1;
+    }
+    return 0;
+}
+
 static int l_gui_getattr(lua::State* L) {
     if (!lua::isstring(L, 1)) {
         throw std::runtime_error("document name is not a string");
@@ -595,6 +620,7 @@ static int l_gui_getattr(lua::State* L) {
             {"data", p_get_data},
             {"parent", p_get_parent},
             {"region", p_get_region},
+            {"options", p_get_options},
         };
     auto func = getters.find(attr);
     if (func != getters.end()) {
@@ -706,9 +732,45 @@ static void p_set_region(UINode* node, lua::State* L, int idx) {
         image->setRegion(UVRegion(vec.x, vec.y, vec.z, vec.w));
     }
 }
+static void p_set_options(UINode* node, lua::State* L, int idx) {
+    if (auto selectbox = dynamic_cast<SelectBox*>(node)) {
+        if (!lua::istable(L, idx)) {
+            throw std::runtime_error("options table expected");
+        }
+        std::vector<SelectBox::Option> options;
+        size_t size = lua::objlen(L, idx);
+        for (size_t i = 0; i < size; i++) {
+            lua::rawgeti(L, i + 1, idx);
+            
+            SelectBox::Option option;
+
+            lua::getfield(L, "value");
+            option.value = lua::require_string(L, -1);
+            lua::pop(L);
+
+            lua::getfield(L, "text");
+            option.text = lua::require_wstring(L, -1);
+            lua::pop(L, 2);
+            
+            options.push_back(std::move(option));
+        }
+        selectbox->setOptions(std::move(options));
+    }
+}
 static void p_set_value(UINode* node, lua::State* L, int idx) {
     if (auto bar = dynamic_cast<TrackBar*>(node)) {
         bar->setValue(lua::tonumber(L, idx));
+    } else if (auto selectbox = dynamic_cast<SelectBox*>(node)) {
+        auto value = lua::require_lstring(L, idx);
+        const auto& options = selectbox->getOptions();
+        for (const auto& option : options) {
+            if (option.value == value) {
+                selectbox->setSelected(option);
+                return;
+            }
+        }
+        selectbox->setSelected(SelectBox::Option {
+            std::string(value), util::str2wstr_utf8(value)});
     }
 }
 static void p_set_min(UINode* node, lua::State* L, int idx) {
@@ -842,6 +904,7 @@ static int l_gui_setattr(lua::State* L) {
             {"cursor", p_set_cursor},
             {"focused", p_set_focused},
             {"region", p_set_region},
+            {"options", p_set_options},
         };
     auto func = setters.find(attr);
     if (func != setters.end()) {

src/logic/scripting/scripting_functional.cpp

@@ -3,6 +3,7 @@
 #include "coders/json.hpp"
 #include "debug/Logger.hpp"
 #include "util/stringutil.hpp"
+#include "util/type_helpers.hpp"
 #include "lua/lua_engine.hpp"
 
 using namespace scripting;
@@ -58,18 +59,44 @@ key_handler scripting::create_key_handler(
     };
 }
 
-wstringconsumer scripting::create_wstring_consumer(
+template<typename T, int(pushfunc)(lua::State*, remove_const_ref_if_primitive_t<const T&>)>
+std::function<void(const T&)> create_consumer(
     const scriptenv& env, const std::string& src, const std::string& file
 ) {
-    return [=](const std::wstring& x) {
+    return [=](const T& x) {
         if (auto L = process_callback(env, src, file)) {
-            lua::pushwstring(L, x);
+            pushfunc(L, x);
             lua::call_nothrow(L, 1);
         }
     };
 }
 
-wstringsupplier scripting::create_wstring_supplier(
+wstringconsumer scripting::create_wstring_consumer(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_consumer<std::wstring, lua::pushwstring>(env, src, file);
+}
+
+stringconsumer scripting::create_string_consumer(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_consumer<std::string, lua::pushstring>(env, src, file);
+}
+
+boolconsumer scripting::create_bool_consumer(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_consumer<bool, lua::pushboolean>(env, src, file);
+}
+
+doubleconsumer scripting::create_number_consumer(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_consumer<number_t, lua::pushnumber>(env, src, file);
+}
+
+template <typename T, T(tovalueFunc)(lua::State*, int)>
+std::function<T()> create_supplier(
     const scriptenv& env, const std::string& src, const std::string& file
 ) {
     return [=]() {
@@ -77,14 +104,32 @@ wstringsupplier scripting::create_wstring_supplier(
             if (lua::isfunction(L, -1)) {
                 lua::call_nothrow(L, 0);
             }
-            auto str = lua::require_wstring(L, -1);
+            auto str = tovalueFunc(L, -1);
             lua::pop(L);
             return str;
         }
-        return std::wstring();
+        return T {};
     };
 }
 
+wstringsupplier scripting::create_wstring_supplier(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_supplier<std::wstring, lua::require_wstring>(env, src, file);
+}
+
+boolsupplier scripting::create_bool_supplier(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_supplier<bool, lua::toboolean>(env, src, file);
+}
+
+doublesupplier scripting::create_number_supplier(
+    const scriptenv& env, const std::string& src, const std::string& file
+) {
+    return create_supplier<number_t, lua::tonumber>(env, src, file);
+}
+
 wstringchecker scripting::create_wstring_validator(
     const scriptenv& env, const std::string& src, const std::string& file
 ) {
@@ -97,60 +142,6 @@ wstringchecker scripting::create_wstring_validator(
     };
 }
 
-boolconsumer scripting::create_bool_consumer(
-    const scriptenv& env, const std::string& src, const std::string& file
-) {
-    return [=](bool x) {
-        if (auto L = process_callback(env, src, file)) {
-            lua::pushboolean(L, x);
-            lua::call_nothrow(L, 1);
-        }
-    };
-}
-
-boolsupplier scripting::create_bool_supplier(
-    const scriptenv& env, const std::string& src, const std::string& file
-) {
-    return [=]() {
-        if (auto L = process_callback(env, src, file)) {
-            if (lua::isfunction(L, -1)) {
-                lua::call_nothrow(L, 0);
-            }
-            bool x = lua::toboolean(L, -1);
-            lua::pop(L);
-            return x;
-        }
-        return false;
-    };
-}
-
-doubleconsumer scripting::create_number_consumer(
-    const scriptenv& env, const std::string& src, const std::string& file
-) {
-    return [=](double x) {
-        if (auto L = process_callback(env, src, file)) {
-            lua::pushnumber(L, x);
-            lua::call_nothrow(L, 1);
-        }
-    };
-}
-
-doublesupplier scripting::create_number_supplier(
-    const scriptenv& env, const std::string& src, const std::string& file
-) {
-    return [=]() {
-        if (auto L = process_callback(env, src, file)) {
-            if (lua::isfunction(L, -1)) {
-                lua::call_nothrow(L, 0);
-            }
-            auto x = lua::tonumber(L, -1);
-            lua::pop(L);
-            return x;
-        }
-        return 0.0;
-    };
-}
-
 int_array_consumer scripting::create_int_array_consumer(
     const scriptenv& env, const std::string& src, const std::string& file
 ) {

src/logic/scripting/scripting_functional.hpp

@@ -23,6 +23,12 @@ namespace scripting {
         const std::string& file = "[string]"
     );
 
+    stringconsumer create_string_consumer(
+        const scriptenv& env,
+        const std::string& src,
+        const std::string& file = "[string]"
+    );
+
     wstringconsumer create_wstring_consumer(
         const scriptenv& env,
         const std::string& src,

src/util/type_helpers.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <type_traits>
+
+template <typename T>
+struct remove_const_ref_if_primitive {
+    using type = T;
+};
+
+template <typename T>
+struct remove_const_ref_if_primitive<const T&> {
+    using stripped_type = typename std::remove_const<typename std::remove_reference<T>::type>::type;
+    using type = typename std::conditional<std::is_fundamental<stripped_type>::value, 
+                                           stripped_type, 
+                                           const T&>::type;
+};
+
+template <typename T>
+struct remove_const_ref_if_primitive<const T> {
+    using stripped_type = typename std::remove_const<T>::type;
+    using type = typename std::conditional<std::is_fundamental<stripped_type>::value,
+                                           stripped_type,
+                                           const T>::type;
+};
+
+template <typename T>
+using remove_const_ref_if_primitive_t = typename remove_const_ref_if_primitive<T>::type;