import Lexer.java

class Parser {

    Lexer lexer;
    Token token;

    public Parser(String s){
        lexer = new Lexer(s + "$");
        token = lexer.nextToken();
    }

    public void run () {
        query();
    }

    public void query () {
        System.out.println("<Query>");
        String val = match(Token.TokenType.KEYWORD);
        System.out.println("\t<Keyword>" + val + "</Keyword>"); //SELECT
        idList();
        String val = match(Token.TokenType.KEYWORD);
        System.out.println("\t<Keyword>" + val + "</Keyword>"); //FROM
        idList();
        String val = match(Token.TokenType.KEYWORD);
        System.out.println("\t<Keyword>" + val + "</Keyword>"); //WHERE
        condList();
        match(Token.TokenType.EOI);
        System.out.println("</Query>");
    }

    public void idList () {
        System.out.println("\t<IdList>");
        String val = match(Token.TokenType.ID);
        System.out.println("\t\t<Id>" + val + "</Id>");
        while (token.getTokenType() == Token.TokenType.COMMA){
          match(Token.TokenType.COMMA);
          System.out.println("\t\t<Comma>,</Comma>");
          val = match(Token.TokenType.ID);
          System.out.println("\t\t<Id>" + val + "</Id>");
        }
        System.out.println("\t</IdList>");
    }

    public void condList(){
      System.out.println("\t<CondList>");
      cond();
      while (token.getTokenType() == Token.TokenType.KEYWORD){ //AND
          String val = match(Token.TokenType.KEWORD);
          System.out.println("\t\t<KEYWORD>" + val + "</KEYWORD>");
          cond();
      }
       System.out.println("\t</CondList>");
    }

    public void cond () {
      System.out.println("\t\t<Cond>");
      String val = match(Token.TokenType.ID);
      System.out.println("\t\t\t<Id>" + val + "</Id>");
      val = match(Token.TokenType.OPERATOR);
      System.out.println("\t\t\t<Operator>" + val + "</Operator>");
      term();
      System.out.println("\t\t</Cond>");
    }



    public void term () {
      System.out.println("\t\t\t<Term>");
      if (token.getTokenType() == Token.TokenType.ID) {
            System.out.println("\t\t\t\t<Id>" + token.getTokenValue()
                               + "</Id>");
        } else if (token.getTokenType() == Token.TokenType.INT) {
            System.out.println("\t\t\t\t<Int>" + token.getTokenValue()
                               + "</Int>");
        } else if (token.getTokenType() == Token.TokenType.FLOAT) {
            System.out.println("\t\t\t\t<Float>" + token.getTokenValue()
                               + "</Float>");
        } else {
            System.err.println("Syntax error: expecting an ID, an int, or a float"
                               + "; saw:"
                               + Token.typeToString(token.getTokenType()));
            System.exit(1);
        }
        System.out.println("\t\t\t</Term>");
    }

    private String match (Token.TokenType tp) {
        String value = token.getTokenValue();
        if (token.getTokenType() == tp)
            token = lexer.nextToken();
        else error(tp);
        return value;
    }

    private void error (Token.TokenType tp) {
        System.err.println("Syntax error: expecting: " + Token.typeToString(tp)
                           + "; saw: "
                           + Token.typeToString(token.getTokenType()));
        System.exit(1);
    }

}