EBoard 11: Pair programming (Section 2)

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

We are back to the standard start-of-class procedure.

Approximate optimistic overview

• Administrative stuff [10 min]
• Some notes on tracing [10 min]
• Questions and answers [5 min]
• An exercise [20 min]
• Reflections on the readings and broader issues [20 min]
• Lab and turn in [15 min]

Administrative stuff

Introductory notes

• Happy Junior Visit Day! I don’t know if we’ll have any visitors.
• I have last Friday’s quizzes mostly graded, but not yet uploaded to Gradescope. Expect to see them tonight.
• Thank you for making it to class on such a cold day!
• Because I care about you, I brought you (discounted) Valentine’s day candy.

Upcoming activities

Scholarly

• Tuesday, 18 February 2025, Noon–12:50 p.m., PDR 224C (White Dining Room). CS Table: The Attention Age
  • Sean Illing. The Real Stakes of the War For Your Attention. Vox – The Gray Area. February 1, 2025. https://www.vox.com/the-gray-area/397131/the-gray-area-chris-hayes-attention-economy (also available as a podcast)
  • Yair Rosenberg. The Worst Page on the Internet. The Atlantic. January 27, 2025. https://www.theatlantic.com/ideas/archive/2025/01/internet-browser-game-website/681461/?gift=irxCS5988mld06tNBmnuK3HS_YPx_iIBSFA9sGb9vjQ&utm_source=copy-link&utm_medium=social&utm_campaign=share
  • You may want to spend a few minutes with the game mentioned in the second article. You can find the game at https://neal.fun/stimulation-clicker/.
• Thursday, 20 February 2025, 11:00 a.m.–noon, JRC 101. Scholars’ Convocation: Steven Geofrey. What Information Worlds Reveal about Climate Change Awareness, Advocacy, and Hope

Artistic

Multicultural

• Friday, 21 February 2025, 4:00–5:00 p.m., HSSC N1170 (Global Living Room). Middle of Everywhere: ???

Peer

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

Wellness

• Tuesday, 18 February 2025, 12:15–12:50 p.m., GCMoA. Yoga in the Museum.
• Tuesday, 18 February 2025, 5:00–6:00 p.m., HSSC S1003 (Atrium). Therapy Dogs.
• Tuesday, 18 February 2025, 4:30–6:30 p.m., BRAC P103 (Multipurpose Dance Studio). Wellness Yoga.
• Tuesday, 18 February 2025, 7:15–8:15 p.m., HSSC S1003 (Atrium). Therapy Dogs.

Misc

• Tuesday, 18 February 2025, 7:00–8:00 p.m., Science 3820. Mentor Session (Quiz prep for Documentation Quiz; Review Tracing)
• Sunday, 23 February 2025, 7:30–8:30 p.m., Science 3819. Mentor Session

Other good things

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

• Monday, 17 February 2025, 8:00–10:00 p.m., Bob’s Underground. Open Mic Night.

Upcoming work

• Monday, 17 February 2025
  • SoLA 1 released at 4:00 p.m.
  • Late submission of MP3
    • Submit MP3 on Gradescope
• Tuesday, 18 February 2025
  • Submit late reflection for MP3 on Gradescope
  • Submit today’s lab on Gradescope
  • Readings:
    • Boolean values and predicate procedures
    • Conditional evaluation
    • Submit reading responses on Gradescope
• Wednesday, 19 February 2025
  • Quiz: Documentation
  • Makeup quiz: Tracing
• Thursday, 20 February 2025
  • Submit Wednesday’s lab on Gradescope
  • Readings:
    • List basics
    • Transforming lists
    • Submit reading responses on Gradescope
  • SoLA 1
    • Decomposition
    • Procedures
    • Primitive types
    • Lambda-free anonymous procedures
    • Collaboration
• Friday, 21 February 2025
  • MP4 released
  • Submit post-reflection for SoLA 1 on Gradescope
• Sunday, 23 February 2025
  • Submit first redo for MP2 on Gradescope
  • Submit Friday’s lab on Gradescope
  • Readings: Processing Lists
    • The “big three” list operations
    • Transforming lists
    • Submit reading responses on Gradescope

Notes on the tracing quiz

Please read the notes on your quiz, even if you got credit.

Do things one step at a time.

NO:

    (+ (* 2 3) (* 4 5))
--> (+ 6 20)

YES:

    (+ (* 2 3) (* 4 5))
--> (+ 6 (* 4 5))
--> (+ 6 20)

Expand all procedures, even ones in which you think you know the result

NO:

    (+ 5 (square 9))
--> (+ 5 81)

YES:

    (+ 5 (square 9))
--> (+ 5 (* 9 9))
--> (+ 5 81)

Finish evaluating each expression before moving on to the next

NO:

    (+ (square (* 2 3)) (square (* 4 5)))
--> (+ (square 6) (square (* 4 5)))
--> (+ (square 6) (square 20))

YES:

    (+ (square (* 2 3)) (square (* 4 5)))
--> (+ (square 6) (square (* 4 5)))
--> (+ (* 6 6) (square (* 4 5)))
--> (+ 36 (square (* 4 5)))
--> (+ 36 (square 20))

Evaluate expressions left-to-right (and inside-out)

NO

    (+ (square (* 2 3)) (square (* 4 5)))
--> (+ (square (* 2 3)) (square 20)

YES

    (+ (square (* 2 3)) (square (* 4 5)))`
--> (+ (square 6) (square (* 4 5)))

Remember how subtraction works

NO

    (+ (- 10 4) (- 2 9))
--> (+ -6 (- 2 9))
--> (+ -6 7)

YES

    (+ (- 10 4) (- 2 9))
--> (+ 6 (- 2 9))
--> (+ 6 -7)

Don’t parenthesize numbers

NO

    (+ 6 (- 2 9))
--> (+ 6 (-7))

YES

    (+ 6 (- 2 9))
--> (+ 6 -7)

Note: Your goal is to keep the expression as valid Scheme the whole way.

Keep the whole context at all times

NO

    (+ (square (+ 2 3)) (square (+ 3 4)))
--> (square (+ 2 3))
--> (square 5)
--> (* 5 5)
--> 25
--> (+ 25 (square (+ 3 4)))

YES

    (+ (square (+ 2 3)) (square (+ 3 4)))
--> (+ (square 5) (square (+ 3 4)))
--> (+ (* 5 5) (square (+ 3 4)))
--> (+ 25 (square (+ 3 4)))

Questions

Administrative

SoLAs

Is “Procedural Abstraction” just a long name for “Procedures”?

Yes.

Do we have to know conditionals?

Not for this SoLA. I’ll fix the page soon.

Do all LAs get posted for everyone, even if we have credit?

Yes. Sorry. I’ll try to send out lists of the ones you’ve done.

Quick overview?

Five separate things on Gradescope. Each with a time limit of one hour.

You can do them all at the same time or one at a time.

Should I open them all at once?

For each LA, you have an hour from the time you open it, so I’d recommend that you finish one before going on to another.

Do we have to do the sample LA?

No.

Background

• Today is our “talk about pair programming” day.
• In our experience, partnering works imperfectly.
  • Some students tend to dominate and are impatient with their partners.
  • Some students feel like they don’t know enough and don’t want to “hold their partner back”.
• We use this day to help make partnering better.
• We will return to these issues throughout the semester.

An exercise

TPS:

• 1 min: Think to yourself for a minute. What did you hear? What would you like to talk about? What made you optimistic? What surprised you? What worried you? What have you encountered already.
• 3 min: Talk to your partner about it
• n min: Full class consideration

What do we want to talk about?

• It’s easier to deal with hitchhikers in this class because the labs don’t have to be completed.
• We should be more intentional in the way we interact with each other.
  • Partners should agree on some principles when they sit down.
• You should be respectful to your classmates.
• It’s surprising that people are judged by how they look or sound.
• Do these things get better as you go up the CS ladder?
  • They sometimes get worse in 161 and 207.
  • Once you hit upper-level classes, most students know each other well enough that they have confidence in their partners.
• Has talking about things made a positive difference? Yes, it seems to. But people backslide (see notes on 161 and 207) and it’s not perfect.
• We don’t always know what our partners are going through … be kind.
• How much of our reactions are due to past experiences?

The “We were getting along … and then they asked me on a date.”

• We laugh when hearing it because there’s a shock factor.
• It creates an odd social dynamic.

Why can’t people meet on Saturdays?

• See above: Everyone has their own situations.
• Many people value Saturday as a break from work. Value their mental health.
• Grinnell already blurs the distinction between schoolwork and life; let people include boundaries.
• Religious obligations may prevent work on Saturdays.
• Athletic obligations may prevent work on Saturdays.

General ways to be intentional in being a good partner.

• Communicate openly - show that you’re engaged.
• Make a conscious effort
• Be self aware - How are you treating your partner?
• If you’re struggling, let your partner know. “I’m sorry, I wasn’t able to do the reading.”
• Pay attention to your partner’s needs and what they are asking for.
• Make sure to let your partner know what you need.
• Volunteer!
• Be socially aware.

Reflecting on the readings (TPS)

What are the key points from the readings? (TPS)

Pair Programming

• Can be very fruitful if there’s good communication.
• However, if you do it incorrectly, it can slow things down. (Don’t try to communicate, one partner ignores the other.)
• When you’re stuck, it helps to talk things out, even to a rubber plant (or stuffed animal or rubber duck), but talking to a human is even better.
• Real pair programming involves working together, not splitting the task.

Couch Potatoes and Hitchhikers

• Stand up for yourself when your partner is not pulling their weight. (But, as we said, make sure you understand that everyone has things going on in their lives.)

Diverse teams

• Some of it was very obvious; people in more accepting cultures work better.
• It’s okay to be a bit uncomfortable in group work; it often leads to better outcomes.
• Preconception: We’re better off working with people that we’re comfortable with. However, the evidence suggests that we do better in groups of people that make us a bit uncomfortable. (Some kinds of uncomfortable are okay, such as when you have different approaches; others aren’t, such as when you aren’t being respected.)

Lab