CSCI 434T

Compiler Design

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Environment Variables

Please add the following line to your .bashrc file in your home directory:

source ~freund/share/setup434

This script just configures Eclipse to use the right version of Java. Open a new terminal window. To verify it is set up correctly, type:

alias eclipse

You should see

alias eclipse='env JAVA_HOME= /opt/eclipse/eclipse -vmargs -Dosgi.locking=none'

Eclipse Basics

In a terminal window run the command
```
  eclipse &
```
If prompted for a workspace name, select the default. (If you already have a workspace, you may wish to create a new one name, for example, workspace434 for this class.) You may be prompted with a dialog about "Scala Diagnostics". Just click "Yes" followed by "Ok". Then click the "Workbench" arrow icon in the main window to go to the workspace.
The Package Explorer on the left lists the projects stored in your workspace. It will be empty. Create a new project by selection "File -> New -> Project" from the menu bar. Select "Java Project" from the list of project options, and click "Next". Then:
- Enter "Test" for the Project name in the next dialog box.
- Click the radio button next to "Use project folder as root for sources and class files".
- Press the "Finish" button.
There should now be a "Test" folder in the Package Explorer.
Select that folder, and select "File -> New -> Class" from the menu bar. Enter "Hello" as the Name in the "New Java Class" dialog box and press finish. The editor panel should show your new class definition. Enter the following definition for a main method:
```
public static void main(String args[]) {
  System.out.println("first arg: " + args[0]);
}
```
Save the file. Eclipse will compile all changed files when you save them, so you never explicitly invoke javac when using Eclipse.
To run the "Test" project, you will create a "run configuration." Select "Run -> Run Configurations..." from the menu. Select "Java Application" from the list on the left-hand side of the "Run" dialog box and then press the "New" button, which is a white box with a little yellow plus on it. Set the "Name" field to be "Hello Config", and make sure that "Project" is "Test" and "Main class" is "Hello."
Now, click on the "Arguments" tab and enter "hello cow" in the "Program variables" box.
Now press the "Run" button, and the output to your program should appear in the "Console" section at the bottom of the Eclipse window.
You can run the program again by selecting "Run -> Run History -> Hello Config" from the menu, or choosing "Hello Config" from the popup list when you click the green circle in the tool bar.
You can also run the program from a terminal window. In a terminal, change directory to ~/workspace/Test, which is the directory on the file system corresponding to the Test project. In that directory, you can run the program as usual:
```
> java Hello hello moo
first arg: hello
```
As always, you can edit the Hello.java file in Emacs if you wish and compile it with javac. However, I encourage you to do all of your editing inside Eclipse, even if you switch to a terminal to run your program (which is how I often work). If you do edit files outside of Eclipse, you should refresh the project inside Eclipse by clicking on the project name in the Package Explorer and selection "File -> Refresh" and then "Project -> Clean..." from the menu.
Warning: Do not rename, move, or delete files from inside the workspace yourself. Perform those operations via the "File" and "Edit" menus inside Eclipse, or else Eclipse will enter a potentially inconsistent state. "Refresh" usually sorts things out...

Setting up SVN

To set up SVN, one person from each group must make a repository directory in which the "master" copy of all files will be stored. To create the repository, open a new terminal window. Enter the following commands:
```
durham:~] svnadmin create svn434
durham:~] chmod o-rwx svn434
durham:~] chmod g+rwx svn434
durham:~] chgrp -R cs434a svn434
```
These commands set up the repository so only your project partners can access it. You will have group names other than cs434a. I will provide your group name.
To give Eclipse access to the repository, you must first configure Eclipse to use SVN:
- Select "Window -> Open Perspective -> Other" from the menu.
- Choose "SVN Repository Exploring". The left panel should now be called "SVN Repositories".
- Click the add icon in that panels toolbar (It is a yellow cylinder with a green plus.)
- Enter the URL:
```
svn+ssh://eringer.cs.williams.edu/home/cs-students/XXX/svn434
```
  where XXX is the user name of your group member who created the repository. Click "Finish", enter your username and password if prompted, and press "Ok". You will also be asked for a new "Master Password". Eclipse stores your password so you don't need to type it in every time you connect to the reposityro. To make this secure, Eclipse uses the "Master Password" to encrypt your Unix password.
Have one person in your group do the following:
- download, unzip, and untar the PA1-Starter code.
- In Eclipse, selection "File -> Import..." from the menu.
- Choose "Existing Projects into Workspace" from under "General". Press the "Next" Button.
- Click "Browse" and choose the "PA1-Starter" directory from where you unpacked it. Press "Choose". The "Import" dialog should then show a checked project named "PA1-Starter".
- Click the box next to "Copy projects into workspace" and press "Finish".
- You may get some errors at this point about build failures. That is fine.
- Select "Window -> Open Perspective -> Java" to switch back to your project mode.
- Selected "Project -> Clean..." and rebuild all projects. You should see text like the following in the console:
```
Reading "ic/lex/ic.flex"
Constructing NFA : 4 states in NFA
Converting NFA to DFA : 
.
3 states before minimization, 2 states in minimized DFA
Writing code to "ic/lex/Lexer.java"
```
  This is JFlex generating your scanner (which also happens automatically inside your Eclipse project).
- Select "File -> Refresh". At this point, no errors should exist.
- Right click on "PA1-Starter" from the Package Explorer. Then select "Team -> Share Project" from the popup menu.
- Select SVN and press "Next".
- Select your repository and press "Next".
- Press "Finish".
- When you reach the "Commit" dialog box. Press "Select All", and THEN DESELECT ic/lex/Lexer.java. (This is the auto-generated file from JFlex that you do not want to keep in your repository.)
- Press OK.
Now, the other members of the group should:
- Fold down the arrow next to your repository name in the left panel of the screen (after selecting "Window -> Open Perspective -> Other..." and "SVN ..." if necessary).
- Select "PA1-Starter" and right click.
- Select "Check Out..." and press finish.
- Switch to the Java Perspective, select the project name, and select "Project -> Clean...".
Everyone now has a working copy of the code.
Have one group member make a change to the Compiler.java file. Select that file in the Package Explorer, right click, and select "Team -> Commit". After committing, have the other group members select the project, right click, and select "Team -> Update". They should all see the change.
We'll now do a few last items to illustrate adding new files, resolving conflicts, etc.