Held: Tuesday, 7 October 2014

Back to Outline 22 - Images as Functions from Position to Colors. On to Outline 24 - Recursion Basics.

Summary

We explore further details of Scheme's lists. Lists are an important mechanism for structuring data. We also consider how lists can be used to represent drawings.

Related Pages

• Reading: Building Data Structures with Heterogenous Lists
• Lab: Building Data Structures with Heterogeneous Lists
• Reference: Important List Procedures
• EBoard 23 (Source 23) (HTML 23)

Overview

• Lists, revisited.
• New list operations.
• Drawings as values.

Administrivia

• New partners!
• Office hours
  • Normal (MThF 1:45-3:15; walking 1:15-1:45)
  • In the Grill 8:00-9:30 Wed and Fri
  • In my office 8:00-9:30 Tue and Thu

Upcoming Work

• Writeup (due Fri): Problem 4, http://bit.ly/151-2014F-w23
• HW 5 due tonight.
• Exam 2 will be distributed tomorrow.
• Reading for Wednesday:
  • Recursion Basics
  • We will spend at least two days on this topic, so don't worry if it seems hard.

Cool Things Coming to Campus

• Two versions of Anna Christie!
• Live Streaming of Verdi's Macbeth, Saturday at 11:55 a.m.
• Pop-up Exhibit, Thursday October 9th, all day in BCA 132

Extra Credit Opportunities

Academic

• Grinnell Prize events this week (particularly events related to the prize winners whose project involves Web tools)
• Artist Talk, Wednesday October 8th at 4:15pm in BCA 152 Rewriting the Application Programming Interface (API) for Art Making
• BCC Faculty Chat, Tuesday, October 14, 7pm

Peer Support

• Football (Saturday at 1pm)
• Swimming October 18: Alumni Weekend
• Karan's radio show 11pm Thursday nights on KDIC
• Evan's radio show 5pm Friday nights on KDIC
• Donna's radio show Sunday midnight on KDIC
• The College's version of Anna Christie, Oct. 9-12 (SB plays Marthy)
• Men's Tennis (???)
• Women's Tennis (???)

Lists

• Our first encounters with lists.
  • Collection of values
  • Homogeneous: All the values in a list are the same type
  • Used primarily with map
• Extending that notion
  • Can also be heterogeneous: Values in the list may have multiple types.
  • Can examine individual elements with car, cdr, and list-ref.
  • Can be extended (creating new lists) with cons.
  • There's an empty list: null.
• Why is the new view important?
  • It will soon give us the opportunity to manipulate lists in new and interesting ways.

Implementing Drawings

• We can (and do) use lists to implement drawings.
• The reading considers a simplified representation, in which the width and height of a drawing are the same.
• But the general process is the same
  • Group the values in a list
  • When we need to render or manipulate a drawing, use the list operations to extract parts.

Lab