CS 142 Compilers Handout 1
Programming Assignment I
Due Friday, April 10, 2009 at 11:55pm
1 Overview
Programming assignments I–IV (or V) will direct you to design and build a compiler for Cool. Each
assignment will cover one component of the compiler: lexical analysis, parsing, semantic analysis, and
code generation. Each assignment will ultimately result in a working compiler phase which can interface
with other phases. You will have an option of doing your projects in C++ or Java.
For this assignment, you are to write a lexical analyzer, also called a scanner or lexer. You will be
writing the lexer “by hand” rather than using a lexical analyzer generator such as lex,flex, or jlex. You
will write code to approximate the function of a DFA by scanning for Cool tokens and then output the
results in the appropriate format. The description of the output and the list of tokens will be provided
for you.
On-line documentation for all the tools needed for the project will be made available on the ECS142
web site. You may work either individualy or in pairs for this assignment. Pairs are encouraged.
2 Files and Directories
To get started, create a directory where you want to do the assignment and execute one of the following
commands in that directory. For the C++ version of the assignment, you should type
gmake -f /home/cs142/s09/cool/assignments/PA2/Makefile
Note that even though this is the first programming assignment, the directory name is PA2. Future
assignments will also have directories that are one more than the assignment number–please don’t get
confused! This situation arises because we are skipping the usual first assignment in this offering of the
course. For Java, type:
gmake -f /home/cs142/s09/cool/assignments/PA2J/Makefile
(notice the “J” in the path name). This command will copy a number of files to your directory. Some of
the files will be copied read-only (using symbolic links). You should not edit these files. In fact, if you
make and modify private copies of these files, you may find it impossible to complete the assignment. See
the instructions in the README file. The files that you will need to modify are:
•lextest.cc / Lexer.java
This file contains starter code to read text file input and call the handwritten lexer below. This file
probably will not need to be modified.
•cool-hand-lex.cc (in the C++ version) / CoolHandLex.java (in the Java version)
This file contains a skeleton for a lexical description for Cool. There are comments indicating where
you need to fill in code, but this is not necessarily a complete guide. Part of the assignment is for you
to make sure that you have a correct and working lexer. Except for the sections indicated, you are
welcome to make modifications to our skeleton. You can actually build a scanner with the skeleton
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