Project 3: Parser

Project 3 Errata list.

Due date: 2004 Sep 29th (Wed) 12:00 Noon

Description

Use JavaCC to construct a parser for our dialect of MiniJava, (as specified below,) that accepts MiniJava source programs and produces abstract syntax trees as specified below.

Project 3 is to be completed in pairs.

Directions

• Before starting this lab, read Chapters 3 & 4 of Appel. In conjunction with the lectures, this will give you a solid foundation for starting your parser.
• To get yourself familiar with JavaCC, you may go to JavaCC and JavaCC Documentation for reference.
• Observe the reference implementation of the parser. It can be run with the command: /homes/cs352/bin/p3 input.java
• You may need to correct your MiniJava grammar to resolve conflicts; please refer to Java Operator Precedence. (Note that some operators don't apply to our MiniJava parser.)
• For this project (and other projects), we will create a set of testcases and then compare the output of your solution to the reference implementation using the utility diff. You will loose points for every testcase that diff returns something. To ensure you have a correct solution, we recommend creating your own set of testcases and then comparing your output to the reference implementation using diff. This process is easily automated using shell scripts. Your TA may discuss this in PSO. No partial credit will be given on testcases that fail.
• Your parser will be graded with automated scripts. Make certain that your project submission can be executed using the following commands:
   
  cd Project3; make; java Parse.Main inputfile.java
   
  where "inputfile.java" is the MiniJava file to be parsed. Failure to follow this simple directory and package naming scheme will result in a zero on the project. If you have not created a Makefile or Java packages before, consult your TA.
• The javacc binary is installed on the lab machines under /p/java2/tools/JavaCC/bin/javacc, and we recommend using the newer version of Java installed under /p/java2/bin/ for this and all remaining projects. Run the setup script /homes/cs352/bin/setup-352 to create a bin directory in your path that points to the new tools and the reference implementation.
• Debug your parser until your abstract syntax trees match the reference implementation.

Other Useful Links

• Java Language Specification
• Textbook Website
• Course Newsgroup

Specification

The MiniJava grammar:

Program	::=	MainClass ( ClassDeclaration )* <EOF>
MainClass	::=	"class" ID "{" "public" "static" "void" "main" "(" "String" "[" "]" ID ")" "{"  (Statement)* "}" "}"
ClassDeclaration	::=	"class" ID "{" ( VarDeclaration )* ( MethodDeclaration )* "}"
	|	"class" ID "extends" ID"{" ( VarDeclaration )* ( MethodDeclaration )* "}"
VarDeclaration	::=	Type ID ";"
MethodDeclaration	::=	"public" Type ID "(" FormalList ")" [ "throws" "java.io.IOException") ] "{" ( VarDeclaration )* ( Statement )* "return" Exp ";" "}"
FormalList	::=	Type ID ( FormalRest)*
	|
FormalRest	::=	"," Type ID
Type	::=	Type "[" "]"
	|	"boolean"
	|	"int"
	|	ID
	|	"String"
Statement	::=	"{" ( Statement )* "}"
	|	"if" "(" Exp ")" Statement [ "else" Statement ]
	|	"while" "(" Exp ")" Statement
	|	"System.out.println" "("  ")" ";"
	|	"System.out.print" "(" Exp ")" ";"
	|	"System.out.write" "(" Exp ")" ";"
	|	ID "=" Exp ";"
	|	ID "[" Exp "]" "=" Exp ";"
Exp	::=	Exp op Exp
	|	Exp "[" Exp "]"
	|	Exp "." "length"
	|	Exp "." ID "(" ExpList ")"
กก	|	Exp ("." ID )+
	|	<DEC_INTEGER_LITERAL>
	|	<STRING_LITERAL>
	|	<HEX_INTEGER_LITERAL>
	|	<OCT_INTEGER_LITERAL>
	|	"System.in.read" "(" ")"
	|	"true"
	|	"false"
	|	"null"
	|	ID
	|	"this"
	|	"new" Type "[" Exp "]" ( "[" "]" )*
	|	"new" ID "(" ")"
	|	"!" Exp
	|	"-" Exp
	|	"~" Exp
	|	"(" Exp ")"
ExpList	::=	Exp ( ExpRest )*
	|
ExpRest	::=	"," Exp
op	::=	"&&"
	|	"||"
	|	"&"
	|	"|"
	|	"^"
	|	"+"
	|	"-"
	|	"*"
	|	"/"
	|	"!="
	|	"=="
	|	"<"
	|	">"
ID	::=	<IDENTIFIER>

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*NOTE:

1. Tokens to be handled are the same as in Project 2, that is, you should use the same definition of operators, punctuation, identifiers, reserved words, integers, (octal, decimal, and hexidecimal,) simple strings, and comments in Project3. (See Specification for Project 2 specification and Appendix A in the textbook.)

2. In the above grammar rules,   "a" denotes the terminal a.

The Abstract Syntax Tree Output:

In this lab you are also required to produce an abstract syntax tree for the parsed program. Unlike previous semesters, you will be creating your own Absyn package and classes to represent the final abstract syntax tree. We will not be providing skeleton code for these classes, nor should you use automated tree builder tools like the Java Tree Builder (JTB). You have a free hand to construct your abstract trees however you like, as long as the work is your own, and the final output conforms to our specifications. Bear in mind, however, that code in both your parser and your abstract suntax trees will be useful in subsequent projects, so write this code with longevity in mind.

The format of the final abstract syntax trees is very simple, and can be gleaned easily from running the reference implementation. Note that whitespace is relevant for readability only, and we will be comparing your output using the -w flag to diff.

What to Turn in

• Submit a directory named Project3 which includes your JavaCC grammar for MiniJava, your source code and a Makefile. Do not submit any binaries or compiled class files.
• Submit using
   
  /homes/cs352/bin/turnin -c cs352=0X01 -p project3 Project3/
   
  on a machine in the CS undergraduate "Lore" domain, where "Project3/" is the name of your project 3 directory, and "0X01" is your division number.

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[Rev 1.05 2004 Sep 26 23:55 DWB]