EBoard 15: Lists, continued, continued (Section 2)

Please follow the standard start-of-class routine.

Warning! You are being recorded (and transcribed) (provided the technology is working correctly).

Approximate overview

• Administrative stuff
• Lab wrapup
• Quiz

Administrative stuff

Introductory Notes

• Today’s lab has a bunch of tests. You can uncomment them by selecting the lines and hitting Ctrl-/. You can re-commend them using the same keypress.
  • Ctrl-; also adds semicolons; Shift-Ctrl-; removes them
  • We’ll be covering testing next Wednesday
• A reminder: DO NOT USE YOUR PHONE IN CLASS! The one exception is when you want to take pictures of the board. If I see you using your phone, I may treat it like I treated the mentor’s phone.
• For those who have missing reading responses: I set the late due date for all reading responses to this Sunday (10/4, good buddy) at 10:30 p.m. I’d encourage you to get those in.
• I’ve rearranged the intoductory material slightly.
• I’m behind on getting MP3 out. Expect it sometime Saturday.

Upcoming work

• Due Sunday, 2026-10-04
  • Today’s lab: More list operations
    • Submit lab writeup on Gradescope
    • Please submit at the end of lab today.
  • Readings:
    • Documenting your code
    • Unit testing
    • Hypothesis-driven debugging
    • Submit reading response on Gradescope
• Due Tuesday, 2026-10-06
  • Mini-project 1 redo
    • When submitting a mini-project redo, please include a file called CHANGES.txt that describes what you’ve changed.
• On Friday, 2026-10-09
  • NEW Quiz/LA on documentation (Monday’s topic)
  • NEW Quiz/LA on testing (Monday’s topic)
  • Makeup Quiz/LA on collaboration
  • Makeup Quiz/LA on lists and list operations
  • Makeup Quiz/LA on conditionals
  • Makeup Quiz/LA on compose, cut, and section
  • Makeup Quiz/LA on tracing
  • Makeup Quiz/LA on decomposition
  • Makeup Quiz/LA on procedures

Upcoming activities

Scholarly

• Friday, 2 October 2026, 4:15–4:45 p.m., HSSC A1231 (the Kernel). Cory McCarten ‘19: What Math and Data Can (and Cannot) Tell us about Gerymandering and Voting Rights
• Friday, 2 October 2026, 5:30–7:30 p.m., Weingart Pavilion. Pioneer Weekend Kickoff
• Monday, 5 October 2026, 4:15–5:15 p.m., HSSC 1325. AI and the Future of Democracy (Highest Recommendation)
• Tuesday, 6 October 2026, Noon–1:00 p.m., JRC 224C (I think). CS Table: Google Zero Updated
• Thursday, 8 October 2026, 11:00 a.m.–noon, JRC 101. Scholars’ Convocation: Alan Schrift: From the Origins of the Grinnell College Center for the Humanities to the Past and Current Crises of the Humanities

CS Table next week will meet in the CS commons, not the dining hall room. The department will provide food (likely Jimmy John’s) so you don’t have to bring food this time.

At our next CS table we will discuss the phenomenon Nilay Patel at The Verge calls Google Zero: when changes to Google Search mean that users make fewer and fewer visits to actual websites, instead relying on AI output or extracted text from Google’s web crawl. We’ll also talk about Google’s recent effort to manage this issue by paying sites for the content they scrape. To prepare for our discussion, please read the two articles linked below:

Kate Conger. Google Is Building an A.I. Fence Around the Internet It Once Championed. The New York Times. July 20, 2026. https://www.nytimes.com/2026/07/20/technology/google-ai-open-web.html?unlocked_article_code=1.zVA.L7zf._L5VDoBJCS4f

Ryan Whitwam. Google’s early attempt to pay websites for AI answers is struggling. Ars Technica. September 30, 2026. https://arstechnica.com/google/2026/09/google-is-paying-100-websites-for-contributions-to-ai-overviews-but-the-amounts-are-tiny/

If you are interested, you can read an account of what this looks like for a small business at https://housefresh.com/david-vs-digital-goliaths/.

Join us at noon in the CS Commons for our weekly discussion of computing and its impact on society. All students, faculty, and staff are welcome to attend.

Artistic/Cultural

• Any day. Visit the GCMOA for at least 30 minutes.
• Friday, 2 October 2026, 7:00 p.m., Wall Theatre. Neverland Players
• Saturday, 3 October 2026, 2:30 p.m., Wall Theatre. Neverland Players
• Saturday, 3 October 2026, 7:00 p.m., Wall Theatre. Neverland Players
• Sunday, 4 October 2026, 2:30 p.m., Wall Theatre. Neverland Players

Multicultural

• Friday, 2 October 2026, 4:10–5:00 p.m., HSSC N1170 Middle of Everywhere (Turkiye)
• Friday, 9 October 2026, 4:10–5:00 p.m., HSSC N1170 Middle of Everywhere (Somewhere)
• Saturday, 10 October 2026, 3:00–5:00 p.m., JRC 101. Walking Tacos with SOL

Peer

Musical, theatric, sporting, academic, and similar events involving this section’s students are welcome.

• Saturday, 3 October 2026, 1:00–4:00 p.m., Rosenbloom Field. Football vs. Knox
• Saturday, 3 October 2026, 1:00–3:00 p.m., Springer Field. Men’s Soccer vs. U. Dubuque

Wellness

• Monday, 5 October 2026, 8:00–9:00 p.m., Prayer Garage. Meditation Group
• Tuesday, 6 October 2026, 4:30–6:00 p.m., Bear P103. Wellness Yoga
• Tuesday, 6 October 2026, 5:00–8:00 p.m., HSSC North Atrium. Therapy Dogs
• Wednesday, 7 October 2026, 11:00 a.m.–1:00 p.m., JRC 1st Floor Lobby. The return of Mom Hugs
• Thursday, 8 October 2026, 11:00 a.m.–3:00 p.m., Goodnow 2nd. Visit the Ombuds for Ombuds Day Updated
  • Get swag.
  • Bring a question for better swag. New
  • Tell Deborah that I sent you.
• Saturday, 10 October 2026, All Day, Somewhere. Mental Health Training
  • Sign up on Handshake.
  • It’s all day, so you will earn 3 tokens.
• Wednesday, 14 October 2026, 4:15–5:45 p.m., Undisclosed Location. Forest Bathing

Misc

• Tuesday, 6 October 2026, 4:15–5:15 p.m., HSSC 1231. Semester at CERA information program
• Wednesday, 7 October 2026, 8:00–9:00 p.m., Science 3820. Mentor Session
• Thursday, 8 October 2026, 4:00–5:15 p.m., Noyce 3821.
  CS Major Information Session
  • We should have snacks beforehand.
• Thursday, 8 October 2026, 8:00–9:00 p.m., Science 3820. Mentor Session

Other good things

These do not earn tokens, but are worth your consideration.

• Saturday, 3 October 2026, 3:30–5:30 p.m., Springer Field. Women’s Soccer vs. U. Dubuque
• Friday, 9 October 2026, 7:00–9:00 p.m., Darby. Volleyball vs. Knox
• Saturday, 10 October 2026, 1:00–3:00 p.m., Darby. Volleyball vs. Illinois

Friday PSA

• Please take care of yourselves this weekend (and every day).
• Choose what is best for yourself.
• If you indulge, please do so in moderation.
• If you cohabit, remember that consent is essential.

Lab

Don’t forget to reload Scamper to ensure that you are using 4.7.0.

The Scheme file should be called list-more.scm.

Note: For some of the problems, you’ll be better off writing a helper function (at least to start). For example, you might want to write a procedure that determines if a string starts with the character s (#\s) or a procedure that checks whether one string is shorter than than another.

Skip the problem that uses string-titlecase.

There’s a problem with exercise 5. More precisely, there’s a problem with the implementation of reduce-left. Use reduce instead.

Quiz

• We’ll hand out the lists quiz and the pictures quiz.
• You can grab any others you want from the back of the room.