Held: Wednesday, 23 September 2015

Back to Outline 15 - Drawings as Values. On to Outline 17 - Programming the GIMP Tools.

Summary

Today we explore Scheme's list data structure and some ways to use lists to make interesting images.

Related Pages

• Reading: Making and Manipulating Homogeneous Lists
• Lab: Making and Manipulating Lists of Drawings
• EBoard 16 (Source 16)

Overview

• Context: What and why lists?
• Building lists.
• Mapping lists.
• Other list operations.

Administrivia

• New partners! You know the drill.
• Review sessions:
  • Wednesday, 8pm (Zachary)
  • Thursday, 10am (Sam)
  • Thursday, 8pm (Caleb)
• It doesn't look like people are using the printed labs/readings, so I'm giving up on them for now. If you need one today, let me know and I'll print one at the start of class.
• Folks are trying to handle the printer problems.
• HW 4 is not quite ready. Expect it to be distributed tonight.

Upcoming Work

• Readings for Friday The GNU Image Manipulation Program and Programming the GIMP tools
• Exam 1
  • Cover sheet due now!
  • Epilogue due TONIGHThttp://bit.ly/151-2015F-exam1epi
• HW 3 to be distributed later.
• Today's Lab writeup (due before class Monday)
  • Email to grader-151-01@cs.grinnell.edu
  • Subject: CSC 151 Lab Writeup Class 15 (Your Names)
  • Exercise:

Extra Credit Opportunities

Academic

• Any visit to the current show in the Faulconer gallery
• No CS Table this week - It's advising week!
• Wednesday CS Extra this week, 4:15 in 3821: Ursula Woltz on Building Coding Communities
• Thursday CS Extra this Week, 4:15 in 3821: SamR on The Architecture of Mediascript

Peer Support

• Pals of PALS, pals@grinnell.edu, normally Saturday at 7:45 am (breakfast included), Sunday at 4:45, and Mondays at 4:45. Requires sign up in advance. Fundraising activity forthcoming, too!
• Pun Club, Saturdays, 4pm, Way over Younker.
• Singers concert on Family weekend! Sept. 26, 2pm., Sebring-Lewis
• Orchestra concert on Family weekend! Sept. 26, 2pm., Sebring-Lewis

Non Extra-Credit Activities

• EE's show in Smith
• Grinnell Homecoming Parade Thursday at 5:30 p.m. - Small town homecoming is an interesting experience that everyone should see once

Context: What Are Lists?

• Issue: We'd like to make images with lots and lots of similar shapes.
• Problem: How to do so systematically.
• Solution: Scheme's list data structure and some related procedures.
• We're learning a new type, so it's useful to figure out some basic issues.

Building Lists

• (list val1 val2 ... valn)
• (make-list n value)
• (iota n)

Mapping Lists

• Basic operation: (map func lst). Apply a function to each element of a list.
• For images, we'll find it easier to do something like
  (map drawing-transform list-of-drawings list-of-values)

Other List Operations

• (append *lst1* *lst2*) - join two lists
• (reverse *lst*) - just what it sounds like
• (list-take *lst* *n*) - take the first n elements of a list
• (list-drop *lst* *n*) - drop the first n elements of a list

Lab

• Do the lab.
• Be prepared to reflect.