code: public void setLeftRight(Expression l, Expression r)
    {
      m_left = l;
      m_right = r;
      l.exprSetParent(this);
      r.exprSetParent(this);
    }
docs: Set the left and right operand expressions for this operation.
  
  
  @param l The left expression operand.
  @param r The right expression operand.