Theo's solution

In this assignment, you will use javacc to generate a lexical analyzer for Tea. Be sure to check the posted grammar solution.

Unlike lex and yacc, the JavaCC tool does not have a separate lexical analyzer generator. We will embed the tokens and the output statements for them within a null parser file.

Here is the outline of the .jj file you will write:

options {
  IGNORE_CASE = false;
  OPTIMIZE_TOKEN_MANAGER = true;
}

PARSER_BEGIN(tea)

import java.io.*;

public class tea {

  public static void main(String[] args) throws FileNotFoundException
  {
    if ( args.length < 1 ) {
       System.out.println("Please pass in the filename for a parameter.");
       System.exit(1);
    }
    
    ASCII_CharStream stream = new ASCII_CharStream(
				  new FileInputStream(args[0]),0,0);
    Token temp_token = null;
    
    teaTokenManager TkMgr = new teaTokenManager(stream);

    do {
        temp_token = TkMgr.getNextToken();

        switch(temp_token.kind) {
         case IF: System.out.println("IF: " + temp_token.image);           
	   break;
	 case TYPEDEF: System.out.println("TYPEDEF: " + temp_token.image);
	   break;

	 .........
	
         default:
           if ( temp_token.kind != EOF )
             System.out.println("OTHER: " + temp_token.image);
           break;
        }
    } while (temp_token.kind != EOF);
  }
}

PARSER_END(tea)

SKIP: /* Whitespace */
{
  "\t"
| "\n"
| "\r"
| " "
}

TOKEN: 
{
  <IF: "if">
| <TYPEDEF: "void" | "int">

.............

| <NUMBER: (["0"-"9"])+>
}

To run JavaCC:

You can use a Makefile similar to Theo's (at '/cs/users/tvd/Makefile'.) or just run JavaCC from his directory. If you have downloaded it into a /bin directory the command is:

JavaCC .../bin/tea.jj

java tea [input file ]

Run your generated lexer on:

(a)
void input_a() {
     a = b3;
     xyz = a + b + c - p / q;
     a = xyz * ( p + q );
     p = a - xyz - p;
}

(b)
void input_b() {
     if ( i > j )
       i = i + j;
     elsif ( i < j )
       i = 1;
}

(c)
void input_c() {
     while ( i < j && j < k ) {
	   k = k + 1;
	   while ( i == j )
		 i = i + 2;
     }
}



(d) A program of your choice. It should test the tokens not tested
in the others. 



 Pass in:  the  JavaCC  source file, input and output from the four programs. 


In this, and all assignments, you will be graded on the appearance and 
documentation of your project. Include your token list as part
of the documentation. You should use a laser printer to print. 






 Send questions and comments to:
Karen Lemone