Assignments should be done using DrRacket (version 7.5), a free instructional development environment tailored for use with the CS 135 textbook. We recommend you download DrRacket and use it on your own computer. DrRacket is available for free for Unix (including Linux), Mac OS X, and Windows.

You can use DrRacket in the Mac Labs on MC third floor. You can use the computer labs anytime, as long as they’re not reserved for other courses (see schedule posted on lab door). To log on to the Macs, you need a password which you can set here: https://www.student.cs.uwaterloo.ca/password/.

For more information, see Assignment 0.


  • Use the exact filenames given at the top of the assignment under “Files to submit”.
  • Use the Racket language level stated.
  • Check the Basic Test results.
  • Do not copy and paste from the Interactions Window into the Definitions window.
  • Do not submit code using the embedded Special Boxes offered by DrRacket, like Comment Boxes.

Non-plaintext Files

There are a variety of ways to turn your Racket program’s file into a “non-plaintext file” – a format that our marking software cannot handle. If you submit an assignment and receive a warning about it, save your file by going to DrRacket: File→Save Other→Save Definitions as Text.

What actions make your file “non-plaintext”? Copy/paste operations from the interactions window or the assignment PDF may do it, depending on the characters included. Inserting Comment Boxes in DrRacket can also do it.