backspace method

Implementation

@override
DartBlockValueTreeBooleanNode? backspace() {
  if (rightChild != null) {
    /// Perform backspace on its right child
    rightChild!.backspace();
    if (operator == null && rightChild == null) {
      /// If the right child becomes null and there is no operator, replace this
      /// composed node with its left child (which can be null)
      return parent?.replaceChild(this, leftChild) ?? leftChild;
    } else {
      /// If it still has an operator, return the composed node.
      return this;
    }
  } else {
    /// If the right child is already null, disregard if there is an operator
    /// and simply replace this composed node with its left child (which can be null).
    /// Important: set the left child's parent to the composed node's parent before
    /// performing this replacement. This step should probably be integrated into the
    /// replaceChild method.
    leftChild?.parent = parent;

    return parent?.replaceChild(this, leftChild) ?? leftChild;
  }
}