[poincare] Navigation and delete in GridLayout.

Change-Id: I8357150d9f15dd003ab97e09981d164d57235739

poincare/src/layout/expression_layout.cpp

@@ -127,7 +127,8 @@ bool ExpressionLayout::hasAncestor(const ExpressionLayout * e) const {
 void ExpressionLayout::addBrother(ExpressionLayoutCursor * cursor, ExpressionLayout * brother) {
   if (m_parent) {
     int brotherIndex = cursor->position() == ExpressionLayoutCursor::Position::Left ? m_parent->indexOfChild(this) : m_parent->indexOfChild(this) + 1;
-    if (m_parent->addChildAtIndex(brother, brotherIndex)) {
+    if (m_parent->isHorizontal()) {
+      m_parent->addChildAtIndex(brother, brotherIndex);
       return;
     }
     if (cursor->position() == ExpressionLayoutCursor::Position::Left) {

poincare/src/layout/grid_layout.cpp

@@ -1,4 +1,5 @@
 #include "grid_layout.h"
+#include "empty_visible_layout.h"
 #include <poincare/expression_layout_cursor.h>
 extern "C" {
 #include <assert.h>
@@ -19,6 +20,30 @@ ExpressionLayout * GridLayout::clone() const {
   return layout;
 }
 
+void GridLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
+  // If the cursor is on the left of the grid, delete the grid and its parent: A
+  // grid only exists for now in binomial coefficient and in matrices, and we
+  // want to delete their parentheses or brackets too.
+  if (cursor->position() == ExpressionLayoutCursor::Position::Left) {
+    int indexOfPointedExpression = indexOfChild(cursor->pointedExpressionLayout());
+    if (indexOfPointedExpression >= 0 && childIsLeftOfGrid(indexOfPointedExpression)) {
+      assert(m_parent != nullptr);
+      assert(m_parent->parent() != nullptr);
+      ExpressionLayout * grandParent = const_cast<ExpressionLayout *>(m_parent->parent());
+      int indexInGrandParent = grandParent->indexOfChild(m_parent);
+      m_parent->replaceWith(new EmptyVisibleLayout(), true);
+      if (indexInGrandParent == 0) {
+        cursor->setPointedExpressionLayout(grandParent);
+        return;
+      }
+      cursor->setPointedExpressionLayout(grandParent->editableChild(indexInGrandParent-1));
+      cursor->setPosition(ExpressionLayoutCursor::Position::Right);
+      return;
+    }
+  }
+  ExpressionLayout::backspaceAtCursor(cursor);
+}
+
 bool GridLayout::moveLeft(ExpressionLayoutCursor * cursor) {
   // Case: Right.
   // Go to the last entry.
@@ -38,7 +63,7 @@ bool GridLayout::moveLeft(ExpressionLayoutCursor * cursor) {
       // Go Left of the grid
       cursor->setPointedExpressionLayout(this);
       cursor->setPosition(ExpressionLayoutCursor::Position::Left);
-      return true;
+      return m_parent->moveLeft(cursor);
     }
     // Case: Left of another child.
     // Go Right of its brother on the left.
@@ -72,10 +97,10 @@ bool GridLayout::moveRight(ExpressionLayoutCursor * cursor) {
   if (childIndex >- 1 && cursor->position() == ExpressionLayoutCursor::Position::Right) {
     if (childIsRightOfGrid(childIndex)) {
       // Case: Right of a child on the right of the grid.
-      // Go Right of the grid.
+      // Go Right of the grid and move Right.
       cursor->setPointedExpressionLayout(this);
       cursor->setPosition(ExpressionLayoutCursor::Position::Right);
-      return true;
+      return m_parent->moveRight(cursor);
     }
     // Case: Right of another child.
     // Go Left of its brother on the right.

poincare/src/layout/grid_layout.h

@@ -9,6 +9,7 @@ class GridLayout : public DynamicLayoutHierarchy {
 public:
   GridLayout(ExpressionLayout ** entryLayouts, int numberOfRows, int numberOfColumns, bool cloneOperands);
   ExpressionLayout * clone() const override;
+  void backspaceAtCursor(ExpressionLayoutCursor * cursor) override;
 
   /* Navigation */
   bool moveLeft(ExpressionLayoutCursor * cursor) override;

poincare/src/layout/horizontal_layout.cpp

@@ -15,6 +15,18 @@ ExpressionLayout * HorizontalLayout::clone() const {
   return layout;
 }
 
+void HorizontalLayout::backspaceAtCursor(ExpressionLayoutCursor * cursor) {
+  // If the cursor was pointing left of the first child of the horizontal
+  // layout, make it point at the horizontal layout itself.
+  if (cursor->position() == ExpressionLayoutCursor::Position::Left) {
+    int indexOfPointedExpression = indexOfChild(cursor->pointedExpressionLayout());
+    if (indexOfPointedExpression == 0) {
+      cursor->setPointedExpressionLayout(this);
+    }
+  }
+  ExpressionLayout::backspaceAtCursor(cursor);
+}
+
 void HorizontalLayout::replaceChild(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild) {
   if (newChild->isEmpty()) {
     if (numberOfChildren() > 1) {

poincare/src/layout/horizontal_layout.h

@@ -9,6 +9,7 @@ class HorizontalLayout : public DynamicLayoutHierarchy {
 public:
   using DynamicLayoutHierarchy::DynamicLayoutHierarchy;
   ExpressionLayout * clone() const override;
+  void backspaceAtCursor(ExpressionLayoutCursor * cursor) override;
 
   /* Hierarchy */
   void replaceChild(const ExpressionLayout * oldChild, ExpressionLayout * newChild, bool deleteOldChild = true) override;