Overview

• Preliminaries.
  • Admin.
  • Upcoming Work.
  • Extra Credit.
  • Questions.
• Exploring the search API.
• Lab.

Preliminaries

Admin

• Continue partners!
• Review sessions Thursday at 9am, 1:15 pm, and 8pm.
  • A particularly good place to ask questions on today's lab :-)
• For office hours this week, check http://rebelsky.youcanbook.me

Upcoming Work

• Quiz Friday: higher-order procedures, analyzing procedures, assoc, and searching.
• Projects due next Tuesday.
• Exam 4 assigned next Monday, due following Monday.
• Lab writeup: Exercise 4. http://bit.ly/151-2015S-lab46
• No reading for Friday. Friday will be project work time (after the quiz).

Extra Credit Opportunities

Academic

• CS Talks Wednesday.
• CS Talks Thursday.
• Diversity as Arbitrage: Silicon Valley and Asian America, Friday, 4:15, Bucksbaum 152.

Peer Support (Afternoon Section)

• Contra Dance. Friday, April 24, at 8pm in Main Hall.
• Dance Ensemble. Thursday 7:30; Friday 7:30; Saturday 7:30; Sunday 2:00. Flanagan. Get tickets!
• Titular head.

Miscellaneous

• Town hall April 23, noon or 7:30 p.m., "How we have conversations."

Other Good Things (no extra credit)

• CS Pub Night Thursday 7:00-8:00 p.m.

Questions

Exploring the search API

;;; Procedure:
;;;   binary-search
;;; Parameters:
;;;   vec, a vector we're searching
;;;   key, the thing we're searching for
;;;   get-key, a procedure that extracts a key from an entry
;;;   may-precede?, a binary predicate (that tells you whether
;;;     the first argument can come before the second argument
;;;     in whatever ordering you're use)
;;; Purpose:
;;;
;;; Produces:
;;;
;;; Preconditions:
;;;    vec is not empty
;;;    vec is ordered by the column.  That is, for all "reasonable" i
;;;       (may-precede? (get-key (vector-ref vec i))
;;;                     (get-keyu (vector-ref vec (+ i 1))))
;;; Postconditions:
;;; Practica:
;;;    (binary-search campus-events-by-name "Contra Dancing"
;;;    (binary-search campus-events-by-location "Main"

Notes:

• We use a vector, rather than a list, because we can quickly get any element of a vector. And binary search requires "look in the middle"

If it helps, here's a set of data, organized by event name

; Each event has name, location, date, expected audience
(define campus-events-by-name
  (vector (list "Contra Dancing" "Main" "2015-04-24" 60)
          (list "Convo-Memory" "JRC 101" "2015-04-22" 100)
          (list "Diversity as Artibrage" "Bucksbaum" "2015-04-24" 6)))
(define campus-events-by-name
  (vector 
   (list "Diversity as Artibrage" "Bucksbaum" "2015-04-24" 6)
   (list "Titular Head" "Harris" "2015-04-25")
   (list "Convo-Memory" "JRC 101" "2015-04-22" 100)
   (list "Contra Dancing" "Main" "2015-04-24" 60)))

Lab