[apps/variable_box] Prepare for Code::VariableBox factorization

apps/Makefile

@@ -34,10 +34,11 @@ apps_src += $(addprefix apps/,\
   lock_view.cpp \
   main.cpp \
   math_toolbox.cpp \
+  math_variable_box_controller.cpp \
+  math_variable_box_empty_controller.cpp \
   shift_alpha_lock_view.cpp \
   suspend_timer.cpp \
   title_bar_view.cpp \
-  variable_box_controller.cpp \
   variable_box_empty_controller.cpp \
 )
 

apps/apps_container.cpp

@@ -85,7 +85,7 @@ MathToolbox * AppsContainer::mathToolbox() {
   return &m_mathToolbox;
 }
 
-VariableBoxController * AppsContainer::variableBoxController() {
+MathVariableBoxController * AppsContainer::variableBoxController() {
   return &m_variableBoxController;
 }
 

apps/apps_container.h

@@ -8,7 +8,7 @@
 #include "apps_window.h"
 #include "empty_battery_window.h"
 #include "math_toolbox.h"
-#include "variable_box_controller.h"
+#include "math_variable_box_controller.h"
 #include "exam_pop_up_controller.h"
 #include "exam_pop_up_controller_delegate.h"
 #include "battery_timer.h"
@@ -34,7 +34,7 @@ public:
   void reset();
   Poincare::Context * globalContext();
   MathToolbox * mathToolbox();
-  VariableBoxController * variableBoxController();
+  MathVariableBoxController * variableBoxController();
   void suspend(bool checkIfOnOffKeyReleased = false);
   bool dispatchEvent(Ion::Events::Event event) override;
   bool switchTo(App::Snapshot * snapshot) override;
@@ -70,7 +70,7 @@ private:
   EmptyBatteryWindow m_emptyBatteryWindow;
   Shared::GlobalContext m_globalContext;
   MathToolbox m_mathToolbox;
-  VariableBoxController m_variableBoxController;
+  MathVariableBoxController m_variableBoxController;
   ExamPopUpController m_examPopUpController;
   OnBoarding::PopUpController m_promptController;
   BatteryTimer m_batteryTimer;

apps/graph/app.cpp

@@ -77,9 +77,9 @@ CodePoint App::XNT() {
 }
 
 NestedMenuController * App::variableBoxForInputEventHandler(InputEventHandler * textInput) {
-  VariableBoxController * varBox = AppsContainer::sharedAppsContainer()->variableBoxController();
+  MathVariableBoxController * varBox = AppsContainer::sharedAppsContainer()->variableBoxController();
   varBox->setSender(textInput);
-  varBox->lockDeleteEvent(VariableBoxController::Page::Function);
+  varBox->lockDeleteEvent(MathVariableBoxController::Page::Function);
   return varBox;
 }
 

apps/math_variable_box_controller.cpp

@@ -1,4 +1,4 @@
-#include "variable_box_controller.h"
+#include "math_variable_box_controller.h"
 #include "shared/global_context.h"
 #include "shared/continuous_function.h"
 #include <escher/metric.h>
@@ -14,7 +14,7 @@ using namespace Poincare;
 using namespace Shared;
 using namespace Ion;
 
-VariableBoxController::VariableBoxController() :
+MathVariableBoxController::MathVariableBoxController() :
   AlternateEmptyNestedMenuController(I18n::Message::Variables),
   m_currentPage(Page::RootMenu),
   m_lockPageDelete(Page::RootMenu),
@@ -25,20 +25,20 @@ VariableBoxController::VariableBoxController() :
   }
 }
 
-void VariableBoxController::viewWillAppear() {
+void MathVariableBoxController::viewWillAppear() {
   assert(m_currentPage == Page::RootMenu);
   AlternateEmptyNestedMenuController::viewWillAppear();
 }
 
-void VariableBoxController::viewDidDisappear() {
+void MathVariableBoxController::viewDidDisappear() {
   AlternateEmptyNestedMenuController::viewDidDisappear();
 
   /* NestedMenuController::viewDidDisappear might need cell heights, which would
-   * use the VariableBoxController cell heights memoization. We thus reset the
-   * VariableBoxController layouts only after calling the parent's
+   * use the MathVariableBoxController cell heights memoization. We thus reset the
+   * MathVariableBoxController layouts only after calling the parent's
    * viewDidDisappear. */
 
-  // Tidy the layouts displayed in the VariableBoxController to clean TreePool
+  // Tidy the layouts displayed in the MathVariableBoxController to clean TreePool
   for (int i = 0; i < k_maxNumberOfDisplayedRows; i++) {
     m_leafCells[i].setLayout(Layout());
     m_leafCells[i].setAccessoryLayout(Layout());
@@ -49,7 +49,7 @@ void VariableBoxController::viewDidDisappear() {
   setPage(Page::RootMenu);
 }
 
-bool VariableBoxController::handleEvent(Ion::Events::Event event) {
+bool MathVariableBoxController::handleEvent(Ion::Events::Event event) {
   /* We do not want to handle backspace event if:
    * - On the root menu page
    *   The deletion on the current page is locked
@@ -68,7 +68,7 @@ bool VariableBoxController::handleEvent(Ion::Events::Event event) {
   return AlternateEmptyNestedMenuController::handleEvent(event);
 }
 
-int VariableBoxController::numberOfRows() const {
+int MathVariableBoxController::numberOfRows() const {
   switch (m_currentPage) {
     case Page::RootMenu:
       return k_numberOfMenuRows;
@@ -81,7 +81,7 @@ int VariableBoxController::numberOfRows() const {
   }
 }
 
-int VariableBoxController::reusableCellCount(int type) {
+int MathVariableBoxController::reusableCellCount(int type) {
   assert(type < 2);
   if (type == 0) {
     return k_maxNumberOfDisplayedRows;
@@ -89,7 +89,7 @@ int VariableBoxController::reusableCellCount(int type) {
   return k_numberOfMenuRows;
 }
 
-void VariableBoxController::willDisplayCellForIndex(HighlightCell * cell, int index) {
+void MathVariableBoxController::willDisplayCellForIndex(HighlightCell * cell, int index) {
   if (m_currentPage == Page::RootMenu) {
     I18n::Message label = nodeLabelAtIndex(index);
     MessageTableCell * myCell = (MessageTableCell *)cell;
@@ -119,7 +119,7 @@ void VariableBoxController::willDisplayCellForIndex(HighlightCell * cell, int in
   myCell->reloadCell();
 }
 
-KDCoordinate VariableBoxController::rowHeight(int index) {
+KDCoordinate MathVariableBoxController::rowHeight(int index) {
   if (m_currentPage != Page::RootMenu) {
     Layout layoutR = expressionLayoutForRecord(recordAtIndex(index), index);
     if (!layoutR.isUninitialized()) {
@@ -129,34 +129,34 @@ KDCoordinate VariableBoxController::rowHeight(int index) {
   return AlternateEmptyNestedMenuController::rowHeight(index);
 }
 
-int VariableBoxController::typeAtLocation(int i, int j) {
+int MathVariableBoxController::typeAtLocation(int i, int j) {
   if (m_currentPage == Page::RootMenu) {
     return 1;
   }
   return 0;
 }
 
-ExpressionTableCellWithExpression * VariableBoxController::leafCellAtIndex(int index) {
+ExpressionTableCellWithExpression * MathVariableBoxController::leafCellAtIndex(int index) {
   assert(index >= 0 && index < k_maxNumberOfDisplayedRows);
   return &m_leafCells[index];
 }
 
-MessageTableCellWithChevron * VariableBoxController::nodeCellAtIndex(int index) {
+MessageTableCellWithChevron * MathVariableBoxController::nodeCellAtIndex(int index) {
   assert(index >= 0 && index < k_numberOfMenuRows);
   return &m_nodeCells[index];
 }
 
-VariableBoxController::Page VariableBoxController::pageAtIndex(int index) {
+MathVariableBoxController::Page MathVariableBoxController::pageAtIndex(int index) {
   Page pages[2] = {Page::Expression, Page::Function};
   return pages[index];
 }
 
-void VariableBoxController::setPage(Page page) {
+void MathVariableBoxController::setPage(Page page) {
   m_currentPage = page;
   resetMemoization();
 }
 
-bool VariableBoxController::selectSubMenu(int selectedRow) {
+bool MathVariableBoxController::selectSubMenu(int selectedRow) {
   m_selectableTableView.deselectTable();
   setPage(pageAtIndex(selectedRow));
   bool selectSubMenu = AlternateEmptyNestedMenuController::selectSubMenu(selectedRow);
@@ -166,7 +166,7 @@ bool VariableBoxController::selectSubMenu(int selectedRow) {
   return selectSubMenu;
 }
 
-bool VariableBoxController::returnToPreviousMenu() {
+bool MathVariableBoxController::returnToPreviousMenu() {
   if (isDisplayingEmptyController()) {
     pop();
   } else {
@@ -176,7 +176,7 @@ bool VariableBoxController::returnToPreviousMenu() {
   return AlternateEmptyNestedMenuController::returnToPreviousMenu();
 }
 
-bool VariableBoxController::selectLeaf(int selectedRow) {
+bool MathVariableBoxController::selectLeaf(int selectedRow) {
   if (isDisplayingEmptyController()) {
     /* We do not want to handle OK/EXE events in that case. */
     return false;
@@ -210,13 +210,13 @@ bool VariableBoxController::selectLeaf(int selectedRow) {
   return true;
 }
 
-I18n::Message VariableBoxController::nodeLabelAtIndex(int index) {
+I18n::Message MathVariableBoxController::nodeLabelAtIndex(int index) {
   assert(m_currentPage == Page::RootMenu);
   I18n::Message labels[2] = {I18n::Message::Expressions, I18n::Message::Functions};
   return labels[index];
 }
 
-Layout VariableBoxController::expressionLayoutForRecord(Storage::Record record, int index) {
+Layout MathVariableBoxController::expressionLayoutForRecord(Storage::Record record, int index) {
   assert(m_currentPage != Page::RootMenu);
   assert(index >= 0);
   if (index >= m_firstMemoizedLayoutIndex+k_maxNumberOfDisplayedRows || index < m_firstMemoizedLayoutIndex) {
@@ -246,30 +246,30 @@ Layout VariableBoxController::expressionLayoutForRecord(Storage::Record record,
   return m_layouts[index-m_firstMemoizedLayoutIndex];
 }
 
-const char * VariableBoxController::extension() const {
+const char * MathVariableBoxController::extension() const {
   assert(m_currentPage != Page::RootMenu);
   return m_currentPage == Page::Function ? Ion::Storage::funcExtension : Ion::Storage::expExtension;
 }
 
-Storage::Record VariableBoxController::recordAtIndex(int rowIndex) {
+Storage::Record MathVariableBoxController::recordAtIndex(int rowIndex) {
   assert(m_currentPage != Page::RootMenu);
   assert(!Storage::sharedStorage()->recordWithExtensionAtIndex(extension(), rowIndex).isNull());
   return Storage::sharedStorage()->recordWithExtensionAtIndex(extension(), rowIndex);
 }
 
-ViewController * VariableBoxController::emptyViewController() {
-  m_emptyViewController.setType((VariableBoxEmptyController::Type)m_currentPage);
+ViewController * MathVariableBoxController::emptyViewController() {
+  m_emptyViewController.setType((MathVariableBoxEmptyController::Type)m_currentPage);
   return &m_emptyViewController;
 }
 
-void VariableBoxController::resetMemoization() {
+void MathVariableBoxController::resetMemoization() {
   for (int i = 0; i < k_maxNumberOfDisplayedRows; i++) {
     m_layouts[i] = Layout();
   }
   m_firstMemoizedLayoutIndex = 0;
 }
 
-void VariableBoxController::destroyRecordAtRowIndex(int rowIndex) {
+void MathVariableBoxController::destroyRecordAtRowIndex(int rowIndex) {
   // Destroy the record
   recordAtIndex(rowIndex).destroy();
   // Shift the memoization if needed

apps/math_variable_box_controller.h

@@ -1,15 +1,13 @@
-#ifndef APPS_VARIABLE_BOX_CONTROLLER_H
-#define APPS_VARIABLE_BOX_CONTROLLER_H
-
-#define MATRIX_VARIABLES 1
+#ifndef APPS_MATH_VARIABLE_BOX_CONTROLLER_H
+#define APPS_MATH_VARIABLE_BOX_CONTROLLER_H
 
 #include "alternate_empty_nested_menu_controller.h"
-#include "variable_box_empty_controller.h"
+#include "math_variable_box_empty_controller.h"
 #include <apps/i18n.h>
 
-class VariableBoxController : public AlternateEmptyNestedMenuController {
+class MathVariableBoxController : public AlternateEmptyNestedMenuController {
 public:
-  VariableBoxController();
+  MathVariableBoxController();
 
   // View Controller
   void viewWillAppear() override;
@@ -32,6 +30,7 @@ public:
     Function = 2
   };
   void lockDeleteEvent(Page page) { m_lockPageDelete = page; }
+
 private:
  constexpr static int k_maxNumberOfDisplayedRows = (Ion::Display::Height - Metric::TitleBarHeight - Metric::PopUpTopMargin - Metric::StackTitleHeight) / Metric::ToolboxRowHeight + 2; // (240 - 18 - 50 - 20) / 40  = 3.8; the 0.8 cell can be above and below so we add +2 to get 5
   constexpr static int k_numberOfMenuRows = 2;
@@ -55,7 +54,7 @@ private:
   Page m_lockPageDelete;
   ExpressionTableCellWithExpression m_leafCells[k_maxNumberOfDisplayedRows];
   MessageTableCellWithChevron m_nodeCells[k_numberOfMenuRows];
-  VariableBoxEmptyController m_emptyViewController;
+  MathVariableBoxEmptyController m_emptyViewController;
   // Layout memoization
   // TODO: make a helper doing the RingMemoizationOfConsecutiveObjets to factorize this code and ExpressionModelStore code
   int m_firstMemoizedLayoutIndex;

apps/math_variable_box_empty_controller.cpp

@@ -0,0 +1,53 @@
+#include "math_variable_box_empty_controller.h"
+#include <poincare/layout_helper.h>
+#include <apps/i18n.h>
+#include <assert.h>
+
+MathVariableBoxEmptyController::MathVariableBoxEmptyView::MathVariableBoxEmptyView() :
+  VariableBoxEmptyView(),
+  m_layoutExample(0.5f, 0.5f, KDColorBlack, Palette::WallScreen)
+{
+  initMessageViews();
+}
+
+void MathVariableBoxEmptyController::MathVariableBoxEmptyView::setLayout(Poincare::Layout layout) {
+  m_layoutExample.setLayout(layout);
+}
+
+void MathVariableBoxEmptyController::viewDidDisappear() {
+  m_view.setLayout(Poincare::Layout());
+}
+
+void MathVariableBoxEmptyController::setType(Type type) {
+  I18n::Message messages[MathVariableBoxEmptyView::k_numberOfMessages] = {
+    I18n::Message::Default,
+    I18n::Message::Default,
+    I18n::Message::Default,
+    I18n::Message::EnableCharacters
+  };
+  Poincare::Layout layout;
+  switch (type) {
+    case Type::Expressions:
+    {
+      messages[0] = I18n::Message::EmptyExpressionBox0;
+      messages[1] = I18n::Message::EmptyExpressionBox1;
+      messages[2] = I18n::Message::EmptyExpressionBox2;
+      const char * storeExpression = "3→A";
+      layout = Poincare::LayoutHelper::String(storeExpression, strlen(storeExpression), MathVariableBoxEmptyView::k_font);
+      break;
+    }
+    case Type::Functions:
+    {
+      messages[0] = I18n::Message::EmptyFunctionBox0;
+      messages[1] = I18n::Message::EmptyFunctionBox1;
+      messages[2] = I18n::Message::EmptyFunctionBox2;
+      const char * storeFunction = "3+x→f(x)";
+      layout = Poincare::LayoutHelper::String(storeFunction, strlen(storeFunction), MathVariableBoxEmptyView::k_font);
+      break;
+    }
+    default:
+      assert(false);
+  }
+  m_view.setMessages(messages);
+  m_view.setLayout(layout);
+}

apps/math_variable_box_empty_controller.h

@@ -0,0 +1,41 @@
+#ifndef APPS_MATH_VARIABLE_BOX_EMPTY_CONTROLLER_H
+#define APPS_MATH_VARIABLE_BOX_EMPTY_CONTROLLER_H
+
+#include <poincare/layout.h>
+#include "variable_box_empty_controller.h"
+
+class MathVariableBoxEmptyController : public VariableBoxEmptyController {
+public:
+  MathVariableBoxEmptyController() :
+    VariableBoxEmptyController(),
+    m_view()
+  {}
+  enum class Type {
+    None = 0,
+    Expressions = 1,
+    Functions = 2
+  };
+  void setType(Type type);
+  // View Controller
+  View * view() override { return &m_view; }
+  void viewDidDisappear() override;
+private:
+  class MathVariableBoxEmptyView : public VariableBoxEmptyView {
+  public:
+    constexpr static int k_numberOfMessages = 4;
+    MathVariableBoxEmptyView();
+    void setLayout(Poincare::Layout layout);
+  private:
+    int numberOfMessageTextViews() const override { return k_numberOfMessages; }
+    MessageTextView * messageTextViewAtIndex(int index) override {
+      assert(index >= 0 && index < k_numberOfMessages);
+      return &m_messages[index];
+    }
+    ExpressionView * expressionView() override { return &m_layoutExample; }
+    MessageTextView m_messages[k_numberOfMessages];
+    ExpressionView m_layoutExample;
+  };
+  MathVariableBoxEmptyView m_view;
+};
+
+#endif

apps/shared/input_event_handler_delegate_app.cpp

@@ -20,9 +20,9 @@ Toolbox * InputEventHandlerDelegateApp::toolboxForInputEventHandler(InputEventHa
 }
 
 NestedMenuController * InputEventHandlerDelegateApp::variableBoxForInputEventHandler(InputEventHandler * textInput) {
-  VariableBoxController * varBox = AppsContainer::sharedAppsContainer()->variableBoxController();
+  MathVariableBoxController * varBox = AppsContainer::sharedAppsContainer()->variableBoxController();
   varBox->setSender(textInput);
-  varBox->lockDeleteEvent(VariableBoxController::Page::RootMenu);
+  varBox->lockDeleteEvent(MathVariableBoxController::Page::RootMenu);
   return varBox;
 }
 

apps/variable_box_empty_controller.cpp

@@ -3,29 +3,28 @@
 #include <apps/i18n.h>
 #include <assert.h>
 
-using namespace Poincare;
-using namespace Ion;
-
-VariableBoxEmptyController::VariableBoxEmptyView::VariableBoxEmptyView() :
-  m_layoutExample(0.5f, 0.5f, KDColorBlack, Palette::WallScreen)
-{
-  for (int i = 0; i < k_numberOfMessages; i++) {
-    m_messages[i].setFont(k_font);
-    m_messages[i].setAlignment(0.5f, 0.5f);
-    m_messages[i].setBackgroundColor(Palette::WallScreen);
-  }
-  m_messages[0].setAlignment(0.5f,1.0f);
-  m_messages[k_numberOfMessages-1].setAlignment(0.5f,0.0f);
-}
-
-void VariableBoxEmptyController::VariableBoxEmptyView::setMessages(I18n::Message *  message) {
-  for (int i = 0; i < k_numberOfMessages; i++) {
-    m_messages[i].setMessage(message[i]);
+// VariableBoxEmptyController::VariableBoxEmptyView
+void VariableBoxEmptyController::VariableBoxEmptyView::initMessageViews() {
+  const int numberOfMessageViews = numberOfMessageTextViews();
+  for (int i = 0; i < numberOfMessageViews; i++) {
+    MessageTextView * message = messageTextViewAtIndex(i);
+    message->setFont(k_font);
+    message->setBackgroundColor(Palette::WallScreen);
+    float verticalAlignment = 0.5f;
+    if (i == 0) {
+      verticalAlignment = 1.0f;
+    } else if (i == numberOfMessageViews - 1) {
+      verticalAlignment = 0.0f;
+    }
+    message->setAlignment(0.5f, verticalAlignment);
   }
 }
 
-void VariableBoxEmptyController::VariableBoxEmptyView::setLayout(Poincare::Layout layout) {
-  m_layoutExample.setLayout(layout);
+void VariableBoxEmptyController::VariableBoxEmptyView::setMessages(I18n::Message * message) {
+  const int numberOfMessageViews = numberOfMessageTextViews();
+  for (int i = 0; i < numberOfMessageViews; i++) {
+    messageTextViewAtIndex(i)->setMessage(message[i]);
+  }
 }
 
 void VariableBoxEmptyController::VariableBoxEmptyView::drawRect(KDContext * ctx, KDRect rect) const {
@@ -33,76 +32,48 @@ void VariableBoxEmptyController::VariableBoxEmptyView::drawRect(KDContext * ctx,
 }
 
 int VariableBoxEmptyController::VariableBoxEmptyView::numberOfSubviews() const {
-  return k_numberOfMessages+1;
+  return numberOfMessageTextViews() + hasExpressionView();
 }
 
 View * VariableBoxEmptyController::VariableBoxEmptyView::subviewAtIndex(int index) {
-  if (index == k_layoutRowIndex) {
-    return &m_layoutExample;
+  if (hasExpressionView()) {
+    if (index == k_expressionViewRowIndex) {
+      return expressionView();
+    }
+    return messageTextViewAtIndex(index + (index < k_expressionViewRowIndex ? 0 : -1));
   }
-  if (index < k_layoutRowIndex) {
-    return &m_messages[index];
-  }
-  return &m_messages[index-1];
+  return messageTextViewAtIndex(index);
 }
 
 void VariableBoxEmptyController::VariableBoxEmptyView::layoutSubviews(bool force) {
-  KDCoordinate width = bounds().width() - 2*k_separatorThickness;
-  KDCoordinate height = bounds().height() - 2*k_separatorThickness;
+  const int numberOfMessageViews = numberOfMessageTextViews();
+  const bool hasExpression = hasExpressionView();
+  KDCoordinate width = bounds().width() - 2 * k_separatorThickness;
+  KDCoordinate height = bounds().height() - 2 * k_separatorThickness;
   KDCoordinate textHeight = k_font->glyphSize().height();
-  KDCoordinate layoutHeight = m_layoutExample.minimalSizeForOptimalDisplay().height();
-  KDCoordinate margin = (height - k_numberOfMessages*textHeight-layoutHeight)/2;
-  m_layoutExample.setFrame(KDRect(k_separatorThickness, k_separatorThickness+margin+k_layoutRowIndex*textHeight, width, layoutHeight), force);
+  KDCoordinate layoutHeight = hasExpression ? expressionView()->minimalSizeForOptimalDisplay().height() : 0;
+  KDCoordinate margin = (height - numberOfMessageViews * textHeight - layoutHeight) / 2;
+  if (hasExpression) {
+    expressionView()->setFrame(KDRect(
+          k_separatorThickness,
+          k_separatorThickness + margin + k_expressionViewRowIndex * textHeight,
+          width,
+          layoutHeight),
+        force);
+  }
   KDCoordinate currentHeight = k_separatorThickness;
-  for (uint8_t i = 0; i < k_numberOfMessages; i++) {
-    if (i == k_layoutRowIndex) {
+  for (uint8_t i = 0; i < numberOfMessageViews; i++) {
+    if (hasExpression && i == k_expressionViewRowIndex) {
       currentHeight += layoutHeight;
     }
-    KDCoordinate h = i == 0 || i == k_numberOfMessages - 1 ? textHeight+margin : textHeight;
-    m_messages[i].setFrame(KDRect(k_separatorThickness, currentHeight, width, h), force);
+    KDCoordinate h = (i == 0 || i == numberOfMessageViews - 1) ? textHeight + margin : textHeight;
+    messageTextViewAtIndex(i)->setFrame(KDRect(k_separatorThickness, currentHeight, width, h), force);
     currentHeight += h;
   }
 }
 
-VariableBoxEmptyController::VariableBoxEmptyController() :
-  ViewController(nullptr),
-  m_view()
-{
-}
+// VariableBoxEmptyController
 
-View * VariableBoxEmptyController::view() {
-  return &m_view;
-}
-
-void VariableBoxEmptyController::viewDidDisappear() {
-  m_view.setLayout(Layout());
-}
-
-void VariableBoxEmptyController::setType(Type type) {
-  I18n::Message messages[VariableBoxEmptyView::k_numberOfMessages] = {I18n::Message::Default, I18n::Message::Default, I18n::Message::Default, I18n::Message::EnableCharacters};
-  Layout layout;
-  switch (type) {
-    case Type::Expressions:
-    {
-      messages[0] = I18n::Message::EmptyExpressionBox0;
-      messages[1] = I18n::Message::EmptyExpressionBox1;
-      messages[2] = I18n::Message::EmptyExpressionBox2;
-      const char * storeExpression = "3→A";
-      layout = LayoutHelper::String(storeExpression, strlen(storeExpression), VariableBoxEmptyView::k_font);
-      break;
-    }
-    case Type::Functions:
-    {
-      messages[0] = I18n::Message::EmptyFunctionBox0;
-      messages[1] = I18n::Message::EmptyFunctionBox1;
-      messages[2] = I18n::Message::EmptyFunctionBox2;
-      const char * storeFunction = "3+x→f(x)";
-      layout = LayoutHelper::String(storeFunction, strlen(storeFunction), VariableBoxEmptyView::k_font);
-      break;
-    }
-    default:
-      assert(false);
-  }
-  m_view.setMessages(messages);
-  m_view.setLayout(layout);
+void VariableBoxEmptyController::setMessages(I18n::Message * messages) {
+  static_cast<VariableBoxEmptyView *>(view())->setMessages(messages);
 }

apps/variable_box_empty_controller.h

@@ -9,36 +9,29 @@
 
 class VariableBoxEmptyController : public ViewController {
 public:
-  VariableBoxEmptyController();
-  enum class Type {
-    None = 0,
-    Expressions = 1,
-    Functions = 2
-  };
+  VariableBoxEmptyController() : ViewController(nullptr) {}
+  void setMessages(I18n::Message * messages);
   // View Controller
-  View * view() override;
   DisplayParameter displayParameter() override { return DisplayParameter::DoNotShowOwnTitle; }
-  void viewDidDisappear() override;
-
-  void setType(Type type);
-private:
+protected:
   class VariableBoxEmptyView : public View, public Bordered {
   public:
-    static constexpr const KDFont * k_font = KDFont::SmallFont;
-    VariableBoxEmptyView();
+    constexpr static const KDFont * k_font = KDFont::SmallFont;
+    void initMessageViews();
     void setMessages(I18n::Message * message);
-    void setLayout(Poincare::Layout layout);
     void drawRect(KDContext * ctx, KDRect rect) const override;
-    constexpr static int k_numberOfMessages = 4;
   private:
+    constexpr static int k_expressionViewRowIndex = 2;
     int numberOfSubviews() const override;
     View * subviewAtIndex(int index) override;
     void layoutSubviews(bool force = false) override;
-    constexpr static int k_layoutRowIndex = 2;
-    MessageTextView m_messages[k_numberOfMessages];
-    ExpressionView m_layoutExample;
+    virtual int numberOfMessageTextViews() const = 0;
+    virtual MessageTextView * messageTextViewAtIndex(int index) = 0;
+    bool hasExpressionView() const {
+      return const_cast<VariableBoxEmptyView *>(this)->expressionView() != nullptr;
+    }
+    virtual ExpressionView * expressionView() { return nullptr; }
   };
-  VariableBoxEmptyView m_view;
 };
 
 #endif