The examination of a witness by the adverse party shall be called his cross-examination. Cross-examination must relate to relevant facts, however, it need not be confined to the facts to which the witness testified on his examination-in-chief. Leading questions may be asked in cross-examination. A person summoned to produce a document does not become a witness by the mere fact that he produced it, and cannot be cross-examined until and unless he is called as a witness. While a witness is being cross-examined he may be asked any question to test his veracity, to discover who he is and his position in life or to shake his credit, by injuring his character which may intend to criminate him directly or indirectly or may expose him to penalty or forfeiture. Such questions are not allowed to ask in examination-in-chief.
