EBoard 04: Reading and Writing Procedures

Getting started

  • Grab a card. It will have a computer name and location.
  • Drop the card in the jar.
  • Navigate to the computer.
  • If you are first, log in.
  • When both partners arrive, introduce yourselves.
  • I think that’s it.

Approximate overview

  • SEPC meeting [5 min]
  • Administrative stuff [5 min]
  • Q&A [5 min]
  • Quick overview of outcomes from last Friday [0 min]
  • Lab [65 min]

Administrative stuff

Welcome to our SEPC (or a subset of the SEPC)

  • Sam thinks they should be called Student Educational Policy, Teaching, and Instruction Committee.
  • Christopher and ….
  • They are here to help you succeed in the CS major
  • There are seven of them.
  • They are a link between students and faculty.
  • They represent you.
  • sepc-cs@grinnell.edu
  • Soon, we will make them wear beanie hats to identify themselves. That was intended as a joke.
  • They will be doing study breaks and re’sume’ workshops (Sam can’t find accents on the Linux keyboard)
  • Let’s build comminity

Introductory Notes

  • Hi, I’m still Sam (or SamR). Our old class mentor is still Eamon Worden. Our new class mentor is Micah Cantor.
  • I’m still working on getting our site up to snuff.
  • Sorry for the non-working autograders. They are on the list of things for me to fix this weekend.
  • Just in case you haven’t been warned: Grinnell holds classes on Labor Day. (Most) Staff have the day off; Faculty and Students (and too many Staff) do not.

Attendance

  • When you are called upon, say your name and something interesting about your partner.

Friday PSA

This is one of my curmudgeonly habits. It comes from a place of care.

  • If you drink, please drink in moderation.
  • If you consume illicit substances, understand their effects and please do them in moderation.
  • Consent is essential

Upcoming activities

Events

  • Grinnellephantitis the weekend of Sep 11/12. 60 minutes suffices.

Upcoming work

Q&A

I’ll reserve time for questions at the start of each class.

Can you explain what we’re supposed to do with the trace?

(define func 
  (lambda (x y z)
    (+ x (* y z))))
;    --> (func (+ 1 2) 3 (* 4 5))
;    --> (func 3 3 (* 4 5))
;    --> (func 3 3 20)
;    --> (+ 3 (* 3 20))
;    --> (+ 3 60)
;    --> 63

Rules of evaluation

  • Evaluate parameters left to right before you apply the procedure
    • Often, it shouldn’t matter which order you do them.
  • If parentheses are nested, you will be evaluating innermost parens before the outermost (+ (* 1 2) 3).
  • When you apply a user-defined function, plug in the actual parameters (aka arguments, actuals) for the formal parameters (aka parameters)

Debrief on Friday’s exercises

Left until Monday, or perhaps never!

What might you have learned from the WowButter and Blackberry Preserve Exercise?

  • We think better in a group than individually.
  • They make something like peanut butter out of soy.
  • We need to be precise in our instructions.
  • Sam is a bit crazy.

Lab

  • Yay! Labs are fun. At least we’ll pretend that because we like Sam. At least we’ll pretend that we like Sam.
  • All of the instructions are in the .rkt file.
  • Make sure that you have procedures.rkt not procedures-a.rkt. Reload the instructions page if you see the wrong link.
  • A “maxim” is a “saying” or “useful statement”. My Web search suggests that it is “a short, pithy statement expressing a general truth or rule of conduct”.
  • Your doors should scale with the house.
  • Yes, you have to do math for the snowcritters. Math is your friend.
  • Eamon says “The driver drives and the navigator navigates. If a navigator grabbed the steering wheel in a car, you would likely crash. So navigators shouldn’t grab the keyboard.”

If you don’t finish …

  • You should find a time to meet with your partner before the next class to finish things up. (Sorry.)
  • You need not complete exercise 5. However, you should make sure you understand how you’d solve it. And yes, you can ask questions in class on Monday.