GetSeparator
BString GetSeparator(BNumberElement element);
parser.SetSeparators(format.GetSeparator(B_DECIMAL_SEPARATOR),
format.GetSeparator(B_GROUPING_SEPARATOR));
fExpressionTextView->Insert(format.GetSeparator(B_DECIMAL_SEPARATOR));
fExpressionTextView->SetValue(result, format.GetSeparator(B_DECIMAL_SEPARATOR));
BString separator(numberFormat.GetSeparator(B_DECIMAL_SEPARATOR));