rv = one->mStr.Compare(two->mStr, PR_FALSE);
rv = one->mStr.CompareWithConversion(two->mStr, PR_FALSE);
  virtual PRInt32 operator()(void* aItem1, void* aItem2) {    OperatorNode* one = (OperatorNode*)aItem1;    OperatorNode* two = (OperatorNode*)aItem2;    PRInt32 rv;    rv = one->mStr.Compare(two->mStr, PR_FALSE);    if (0 == rv) {      nsOperatorFlags form1 = NS_MATHML_OPERATOR_GET_FORM(one->mFlags);      nsOperatorFlags form2 = NS_MATHML_OPERATOR_GET_FORM(two->mFlags);      if (form1 == form2) return 0;      else {        rv = (form1 < form2) ? -1 : 1;        // Record that the operator was found in a different form.        // We don't know which is the input, we grab both of them and         // we check later (see below).        gOperatorFound[form1] = one;        gOperatorFound[form2] = two;      }    }    return rv;  }