public static void main(String args[]) {
        
        if (args.length!=1){
            System.out.println("Not the proper usage dude, try: java Lexer <filename>");
            System.exit(-1);
        } 
          
        String fileName = args[0];
        Token tok;
        try {
            Lexer lex = new Lexer(fileName);
            while (true) {
                tok = lex.nextToken();
                if ((tok.getKind() == Tokens.Identifier) ||
                    (tok.getKind() == Tokens.INTEGER) ||
                     tok.getKind() == Tokens.FLOAT){
                    System.out.printf("%-10s" ,tok.toString());
                } else {
                    System.out.printf("%-10s" ,tok.getKind().toString());
                }
                
                String p = "left: " + tok.getLeftPosition() +
                   " right: " + tok.getRightPosition() + "  " 
                    + "line: " + tok.getLineNumber();
                System.out.println(p);
            }
        } catch (Exception e) {}
    }