parsePresence static method

QueryParserState? parsePresence(QueryParser parser)

Implementation

static QueryParserState? parsePresence(QueryParser parser) {
  var lexeme = parser.consumeLexeme();

  if (lexeme == null) {
    return null;
  }

  switch (lexeme.str) {
    case "-":
      parser.currentClause.presence = QueryPresence.PROHIBITED;
      break;
    case "+":
      parser.currentClause.presence = QueryPresence.REQUIRED;
      break;
    default:
      var errorMessage = 'unrecognised presence operator ${lexeme.str}';
      throw QueryParseError(errorMessage, lexeme.start, lexeme.end);
  }

  var nextLexeme = parser.peekLexeme();

  if (nextLexeme == null) {
    var errorMessage = "expecting term or field, found nothing";
    throw QueryParseError(errorMessage, lexeme.start, lexeme.end);
  }

  switch (nextLexeme.type) {
    case LexemeType.FIELD:
      return QueryParser.parseField;
    case LexemeType.TERM:
      return QueryParser.parseTerm;
    default:
      var errorMessage = 'expecting term or field, found ${nextLexeme.type}';
      throw QueryParseError(errorMessage, nextLexeme.start, nextLexeme.end);
  }
}