EECS 321: Programming Languages

LectureTech LR5; Tuesdays and Thursdays 11:00—12:20

TextProgramming Languages: Application and Interpretation (First Edition)
by Shriram Krishnamurthi


SoftwareHandin Status

quick-ref.rkt a quick reference to things Racket; open in DrRacket

Vincent St-Amour
Office Hours: Wednesdays 4-5 or by appointment, Mudd 3215

Spencer Florence, Emily Blackman, Hakan Dingenc, Kate Hayner-Slattery, Jeremy Kaish, Patrick Sachaj, and Nathan Shelly
Office Hours: Mudd 3534 collaboration space
Mondays: 6pm-8pm
Tuesdays: 1pm-3pm (in Mudd 3532), 3pm-5pm (in Mudd 3532), 6pm-8pm
Wednesdays: 10am-noon, 2pm-4pm, 6pm-8pm
Thursdays: 1pm-3pm (in Mudd 3303), 6-8pm
Fridays: 10am-noon

Week #DateTopicReadings
1Thursday, September 27th, 2018Introduction
01a-intro.pdf 01b-plai.pdf
PLAI §1, §2
2Due: Noon on Monday, October 1st, 2018HW 1: Setup and Finger Exercises
2Tuesday, October 2nd, 2018Variables and Binding
2Thursday, October 4th, 2018Functions and Parsing
2Due: Noon on Friday, October 5th, 2018HW 2: Binding
3Tuesday, October 9th, 2018Deferred Substitution
3Thursday, October 11th, 2018Random Testing
3Due: Noon on Friday, October 12th, 2018HW 3: Multi-Argument Functions
4Tuesday, October 16th, 2018Higher-Order Functions
4Thursday, October 18th, 2018Capture-Avoiding Substitution, Compilation
07a-capture-avoiding-substitution.pdf 07b-compilation.pdf
4Due: Noon on Friday, October 19th, 2018HW 4: Deferred Substitution
5Tuesday, October 23rd, 2018Higher-order Functions II, Recursion
08a-higher-order-functions-2.pdf 08b-recursion.pdf
PLAI §6, §9
5Thursday, October 25th, 2018Recursion II, State
09a-recursion-2.pdf 09b-state.pdf
PLAI §10, §12, §13
5Due: Noon on Friday, October 26th, 2018HW 5: Higher-Order Functions
6Tuesday, October 30th, 2018State II
PLAI §13
6Thursday, November 1st, 2018Control
PLAI §18, §19
6No Homework on Friday, November 2nd, 2018 
7Tuesday, November 6th, 2018Garbage Collection: Intro
PLAI §21
7Thursday, November 8th, 2018Garbage Collection: Mark-and-Sweep
7Due: Noon on Friday, November 9th, 2018HW 6: State
8Tuesday, November 13th, 2018Garbage Collection: Mark-and-Sweep
13-14-gc-mark-and-sweep.pdf (cont'd)
8Thursday, November 15th, 2018Garbage Collection: Copying, Types: Intro
15a-gc-copying.pdf 15b-types-intro.pdf
PLAI §24
8Due: Noon on Friday, November 16th, 2018HW 7: Control
9Tuesday, November 20th, 2018Types: Typing Rules
PLAI §25
9Thursday, November 22nd, 2018Thanksgiving
9No Homework on Friday, November 23rd, 2018 
10Tuesday, November 27th, 2018Types: Typechecking
10Thursday, November 29th, 2018Types: Type Soundness, Extensions
18a-type-soundness.pdf 18b-types-extensions.pdf
PLAI §28
10Due: Noon on Friday, November 30th, 2018HW 8: Garbage Collection
11Tuesday, December 4th, 2018Types: Type Inference
PLAI §30
11Thursday, December 6th, 2018Generational GC & Cheney on the MTA
20a-generational-gc.pdf 20b-recap.pdf
11Due: Noon on Friday, December 7th, 2018HW 9: Types


Your homework each week will be graded automatically and you will receive either a check+ (A), check (B), check- (C), or 0 (F).

When computing your final grade, a check+ is treated like a 9, a check is treated like an 7, a check- is treated like 6, and a 0 is treated like a 0. The numbers are then averaged and this function is used to map them into number grades:

(define (numeric-grade->letter-grade number)
   ((<= 8.3 number 9) 'A)
   ((<= 7.8 number 8.3) 'A-)
   ((<= 7.4 number 7.8) 'B+)
   ((<= 7.0 number 7.4) 'B)
   ((<= 6.4 number 7.0) 'B-)
   ((<= 6.0 number 6.4) 'C)
   ((<= 5.0 number 6.0) 'C-)
   ((<= 4 number 5) 'D)
   ((<= number 5) 'F)))

Homeworks are due on Fridays at noon. You can expect grades to be out on the following Monday. Failing that, you will have heard from the course staff regarding when to expect them.

To encourage you to revisit material you have ot yet mastered, you have the option to resubmit homework assignments after their original deadline. If your understanding of that homework has improved, hopefully so should your grade.

Each homework has two resubmission deadlines: hwN-second-round at noon the Friday following the original deadline, and hwN-third-round at noon the Friday two weeks after the original deadline. You can submit to any of the three deadlines for a homework independently. E.g., you don't need to submit to the second round to be allowed to submit to the third, etc. Resubmission grading follows the same schedule described above. Late submissions will not be accepted.

Resubmission grades are capped to an 8, halfway between a check and a check+. I.e., if you get a check+ on a resubmission, it counts as an 8.

The last time second-try assignments will be accepted is Wednesday of finals week (December 12th), 5pm.


Collaboration is a really good thing and we encourage it. On the other hand, cheating is a very serious offense, which carries serious consequences. It's OK to meet with colleagues, form study groups, discuss assignments with them, or compare alternative approaches. But it is never ok to share code or homework solutions, or even to see each other's code or solutions. What you turn in must be your own work. Copying (or even studying) code, solutions, etc., from anywhere (e.g., other people, web, GitHub) is strictly prohibited. Be aware that we use the (highly effective) MOSS software similarity detection system. If you discuss your work with another group, please list their names in your hand-in.

It is also forbidden to share, post, or otherwise publicise your solutions. This even extends after the quarter ends. No matter how proud you are of them, no posting your solutions to GitHub; doing so is an invitation to plagiarism.

It is the responsibility of every student in this class to be familiar with and to adhere to the Academic Integrity Policies of Northwestern University and the McCormick School of Engineering. The policies can be found here.

Any suspicion of violation of these policies will be reported immediately to the Associate Dean for Undergraduate Studies. If you are in doubt whether your actions constitute a violation of the above policies, ask the instructor.