[poincare] Dividing 3E-2 in Natural edition should give (3E-2)/|

poincare/include/poincare/char_layout.h

@@ -17,6 +17,7 @@ public:
 
   // CharLayout
   virtual void setChar(char c) { m_char = c; }
+  char character() const { return m_char; }
   const KDFont * font() const { return m_font; }
   void setFont(const KDFont * font) { m_font = font; }
 
@@ -24,6 +25,7 @@ public:
   void moveCursorLeft(LayoutCursor * cursor, bool * shouldRecomputeLayout) override;
   void moveCursorRight(LayoutCursor * cursor, bool * shouldRecomputeLayout) override;
   int serialize(char * buffer, int bufferSize, Preferences::PrintFloatMode floatDisplayMode, int numberOfSignificantDigits) const override;
+  bool isChar() const override { return true; }
   bool isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const override;
 
   // TreeNode
@@ -55,8 +57,10 @@ private:
 
 class CharLayout final : public Layout {
 public:
+  CharLayout(const CharLayoutNode * n) : Layout(n) {}
   CharLayout(char c, const KDFont * font = KDFont::LargeFont);
   const KDFont * font() const { return const_cast<CharLayout *>(this)->node()->font(); }
+  char character() const {return const_cast<CharLayout *>(this)->node()->character();}
 private:
   using Layout::node;
   CharLayoutNode * node() { return static_cast<CharLayoutNode *>(Layout::node());}

poincare/include/poincare/layout.h

@@ -45,6 +45,7 @@ public:
   bool isMatrix() const { return const_cast<Layout *>(this)->node()->isMatrix(); }
   bool isVerticalOffset() const { return const_cast<Layout *>(this)->node()->isVerticalOffset(); }
   bool isLeftParenthesis() const { return const_cast<Layout *>(this)->node()->isLeftParenthesis(); }
+  bool isChar() const { return const_cast<Layout *>(this)->node()->isChar(); }
   bool isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const { return const_cast<Layout *>(this)->node()->isCollapsable(numberOfOpenParenthesis, goingLeft); }
   int leftCollapsingAbsorbingChildIndex() const { return const_cast<Layout *>(this)->node()->leftCollapsingAbsorbingChildIndex(); }
   int rightCollapsingAbsorbingChildIndex() const { return const_cast<Layout *>(this)->node()->rightCollapsingAbsorbingChildIndex(); }

poincare/include/poincare/layout_node.h

@@ -103,6 +103,7 @@ public:
   virtual bool isRightBracket() const { return false; }
   virtual bool isEmpty() const { return false; }
   virtual bool isMatrix() const { return false; }
+  virtual bool isChar() const { return false; }
   virtual bool hasUpperLeftIndex() const { return false; }
   virtual char XNTChar() const {
     LayoutNode * p = parent();

poincare/src/char_layout.cpp

@@ -32,17 +32,35 @@ int CharLayoutNode::serialize(char * buffer, int bufferSize, Preferences::PrintF
 }
 
 bool CharLayoutNode::isCollapsable(int * numberOfOpenParenthesis, bool goingLeft) const {
-  if (*numberOfOpenParenthesis <= 0
-      && (m_char == '+'
-        || m_char == '-'
+  if (*numberOfOpenParenthesis <= 0) {
+    if (m_char == '+'
         || m_char == '*'
         || m_char == Ion::Charset::MultiplicationSign
         || m_char == Ion::Charset::MiddleDot
         || m_char == Ion::Charset::Sto
         || m_char == '='
-        || m_char == ','))
-  {
-    return false;
+        || m_char == ',')
+    {
+      return false;
+    }
+    if (m_char == '-') {
+      /* If the expression is like 3E-200, we want '-' to be collapsable.
+       * Otherwise, '-' is not collapsable. */
+      Layout thisRef = CharLayout(this);
+      Layout parent = thisRef.parent();
+      if (!parent.isUninitialized()) {
+        int indexOfThis = parent.indexOfChild(thisRef);
+        if (indexOfThis > 0) {
+          Layout leftBrother = parent.childAtIndex(indexOfThis-1);
+          if (leftBrother.isChar()
+              && static_cast<CharLayout&>(leftBrother).character() == Ion::Charset::Exponent)
+          {
+            return true;
+          }
+        }
+      }
+      return false;
+    }
   }
   return true;
 }