(a) After Trial or Hearing or by Agreement. Subject to the provisions of Rule 54(b) : (1) Upon a decision by the court that a party shall recover only a sum certain or costs or that all relief shall be denied, or upon a written agreement for judgment for a sum certain or denying relief, the court shall forthwith prepare, sign and enter judgment; (2) upon a decision by the court granting other relief, the court shall promptly approve the form of the judgment. Every judgment shall be set forth on a separate document. A judgment is effective only when so set forth and when entered as provided in Rule 79(a) . Entry of the judgment shall not be delayed for the taxing of costs. Attorneys shall submit forms of judgment upon direction of the court. All judgments in cases governed by these rules shall enter within thirty days after completion of trial.
(c) Nisi Judgment. At any time before the expiration of ninety days from the entry of a judgment of divorce nisi, the defendant, or any other person interested, may file in the Registry of Probate a statement of objections to the judgment becoming absolute, which shall set forth specifically the facts on which it is founded and shall be verified by affidavit. Notice of the filing of said objections shall be given to the plaintiff or defendant or his attorney, not later than the day of filing said objections. The portion of the judgment to which any objection is filed, but only that portion, shall not become absolute until such objections have been disposed of by the court. If said petition to stay the judgment absolute is subsequently dismissed by the court, the judgment shall become absolute as of ninety days from the date of the judgment nisi.