--- title: Eboard 30 Higher-order procedures, revisited number: 30 section: eboards held: 2019-04-17 link: true --- CSC 151 2019S, Class 30: Higher-order procedures, revisited ============================================================ _Overview_ * Preliminaries * Notes and news * Upcoming work * Extra credit * Questions * Key ideas * Lab * Mentor surveys Preliminaries ------------- ### News / Etc. * Mentor sessions Thursday 7-8 p.m., Thursday 8-9 p.m., Sunday 5-6 p.m. * Note change in schedule. * Folks should think about taking CSC 161 in the fall. It's a great class, and you get to work with robots! * I will need to leave class early today and Friday to observe a colleague's class. Friday we'll do the quiz at the end of class. Today we'll have mentor surveys at the end of class. ### Upcoming work * [Project proposal](../project) due Monday night. * Friday's quiz: Pairs, Vectors * Reading for Friday: [Analyzing procedures](../readings/analysis) * Flash cards tonight: Pairs, Vectors * Lab writeup: TBD ### Extra Credit _I would certainly appreciate suggestions of other extra credit activities (preferably via email)._ #### Extra credit (Academic/Artistic) * Any student research week activity. (Still some on Thursday.) * The Magic Flute, April 18, 7:00 p.m. Sebring-Lewis * **New**: Dartanyan Brown discussion, 4pm Wednesday April 24, HSSC S3325 * **New**: Dartanyan Brown concert, 7:30 pm Wednesday April 24, Sebring-Lewis #### Extra credit (Peer) * Track and Field at home this Saturday. (30 min) * Women pole vault at about 10am * Then men (noon?) * Running likely to be between noon and 1pm * Women's Golf at Beloit this weekend. #### Extra credit (Wellness) #### Extra credit (Wellness, Regular) * 30 Minutes of Mindfulness at SHACS (SHAW) every Monday 4:15-4:45 * Any organized exercise. (See previous eboards for a list.) * 60 minutes of some solitary self-care activities that are unrelated to academics or work. Your email reflection must explain how the activity contributed to your wellness. * 60 minutes of some shared self-care activity with friends. Your email reflection must explain how the activity contributed to your wellness. #### Extra credit (Misc) * CS Internship Hour, Thursday, 6:30-7:30 p.m., Noyce 3821. _Free Pizza_. * Participate in Kinetic Sculpture Competition: Saturday the 27th * * You'll need to build your sculpture in advance. * You get reimbursed for up to $200 in supplies, but must present to be reimbursed. * Public speaking workshop - April 22 at 7pm in HSSC S3325, with Kathy Clemons-Beasley '05. "Kathy is the Global head of Leadership and Manager Development for Blackrock and has been the speaker coach for TEDxGC." * Clothing donation boxes in lounges. Donate! ### Other good things ### Questions What's my grade in the class? ```drracket (define grade (lambda (participation cards labs hw project quizzes exams best) (+ (* 0.05 participation) ; 90% is my default (* 0.05 cards) (* 0.10 labs) (* 0.15 hw) (* 0.10 project) (* 0.10 quizzes) (* 0.40 exams) (* 0.05 best)))) Plus extra credit (* 0.0025 num-extra-credit) ``` Key ideas --------- _What did you see as the key (new) ideas from the reading?_ * Seeing patterns is important in CS and programming. * Once you see a pattern, you can write a procedure that encapsulates that pattern, often by adding another procedure as a parameter, so that you don't have to write the whole same code again. * l-s and r-s are there. They are like section, but simpler * Looking for more general solutions is good. * We've seen procedures that take other procedures as parameters, such as `map`. There's nothing special about them; we could write them ourselves. * We can return procedures as results, generally by using an extra lambda to describe the procedure. * One new hop: `apply` _Sectioning_ ```drracket (l-s proc x) = (section proc x <>) (r-s prox x) = (section proc <> x) ``` ```drracket (define l-s (lambda (proc left) ; Inputs to l-s (lambda (right) ; Input to the procedure created by l-s (proc left right)))) ; Body of the procedure created by l-s (define r-s (lambda (proc right) ; inputs to r-s (lambda (left) ; input to the new procedure (proc left right)))) ; body ``` How is apply different than reduce? > Do the lab and you'll figure it out. How do we write procedures like `map` and `+` that take an unlimited number of arguments. > Not covered yet. Ask me offline. More seriously, `(lambda params body)`, when you don't put the params in parentheses, bundles all of the parameters into a list, no matter how many there are. (define num-params (lambda params (length params))) > (num-params) 0 > (num-params 'a) 1 > (num-params 'a 'b 'c 'd) 4 > (num-params (list 'a 'b)) 1 Lab --- ```drracket (define increment (section + 1 <>)) (define iota range) (define square sqr) ``` Sam's favorite quote of today's class (approx): "The one with `o` is the clearest, but I often forget to use `o` when I write programs." Writeup: Exercise 5 Mentor survey ------------- The mentor and tutor surveys are an important part of our peer educator program. Please take them seriously.