sS gazelle_copyRuleWithNewFirstIn(S ruleID, S newFirstIn) {
  PairS p = dm_textAndCommentOfRule(ruleID);
  if (p == null) null;
  S newText = gazelle_replaceFirstInOfRuleText(p.a, newFirstIn);
  if (newText == null) null;
  gazelle_addRuleWithComment(newText, p.b);
  ret dm_gazelle_addRuleWithComment_msg!;
}