code: private AstStrList parseStringList() {
      ArrayList<String> strs = new ArrayList<>(10);
      while (isQuote(skipWS())) {
        strs.add(string());
        if (skipWS() == ',') eatChar(',');
      }
      return new AstStrList(strs);
    }
docs: Parse a list of strings. Strings can be either in single- or in double quotes.