private String GetErrorPrefix( Int32?fileId, Int32?line, Int32?column) { if (fileId != null) { var fileName = GetFileName(fileId.Value); if (line != null && column != null) { return($"{fileName} {TemplateStrings.LineColumn(line, column)}:"); } else { return($"{fileName}:"); } } else if (line != null && column != null) { return($"{TemplateStrings.LineColumn(line, column)}:"); } else { return(String.Empty); } }