Guide on how to install Java, Jflex and CUP in the macOS operating system.

THIS GUIDE FOR NOW WAS CHECKED ONLY BY ONE STUDENT, AS A CONSEQUENCE IF YOU FOUND ERRORS OR SOME PASSAGES THAT CAN BE SIMPLIFIED, PLEASE LET ME KNOW BY SENDING AND EMAIL.

The Oracle JDK can be downloaded at the following address https://www.oracle.com/java/technologies/javase-downloads.html, choosing the one marked as Windows x64 Installer (at the moment of this guide the recommended version to download is jdk-15.0.2_osx-x64_bin.tar.gz).

To install Java a possible guide is the following:

1. Create a folder into your home directory
   

   cd
   mkdir -p compilers
   cd compilers

2. Download into the folder the Java installation file jdk-15.0.2_osx-x64_bin.tar.gz.
3. Decompress it
   

   tar xvfz jdk-15.0.2_osx-x64_bin.tar.gz

To install JFlex and CUP follow the following steps:

1. To install Jflex execute the command

   brew install jflex

2. Copy the folders java_cup_v11_draw_tree (that you can find in this zip file) inside compilers, in order to have the path /home/skenz/compilers/java_cup_v11_draw_tree.
3. Enter the CUP directory

   cd java_cup_v11_draw_tree/java_cup

4. Compile CUP:

   javac *.java runtime/*.java ../StdDraw.java

Before running CUP and Jflex, environment variables must be configured.

To set the environment variables, open in your home directory the file .zshrc (the .zshrc file is executed by the shell each time you open a terminal and usually it is used to configure a shell):

cd
touch .zshrc
open .zshrc

After opening the .zshrc file, add on its top the following lines:

PATH=$PATH:.:/Users/skenz/compilers/java_cup_v11_draw_tree/java_cup/:/Users/skenz/compilers/jflex-1.8.2/bin
export PATH
CLASSPATH=.:/Users/skenz/compilers/java_cup_v11_draw_tree/
export CLASSPATH

Note: to make active the new environment variables you must reopen a new shell. Remember that both $PATH and $CLASSPATH environmental variables have to contain the . (dot) that represents the current directory.

To verify that the programs have been installed correctly, open a command prompt (cmd) and enter:

jflex

A graphical window should be opened.

For CUP you can type into the command prompt:

java java_cup.Main

and if it is correctly installed you see nothing in the terminal. To stop it you can press CTRL-c.

The installed CUP version contains also the functionality to draw into the screen the parse tree (this version was made especially for this course). To check this part you can type into the command prompt:

java java_cup.MainDrawTree

and if it is correctly installed you see nothing in the terminal. To stop it you can press CTRL-c.

1. Download the following code: exClass-2.zip
2. Decompress in a directory end type in a terminal the following commands

jflex scanner.jflex
java java_cup.MainDrawTree parser.cup
javac *.java
java Main example_expr.txt