// Internal node
public class VarIntlNode implements VarBinNode {
  private VarBinNode left;                // Left child
  private VarBinNode right;               // Right child
  private Character operator;             // Operator value

  VarIntlNode(Character op, VarBinNode l, VarBinNode r)
    { operator = op; left = l; right = r; }
  public boolean isLeaf() { return false; }
  public VarBinNode leftchild() { return left; }
  public VarBinNode rightchild() { return right; }
  public Character value() { return operator; }
}