1 12687dd9 2023-08-04 jrmu ;; The first three lines of this file were inserted by DrScheme. They record metadata
 2 12687dd9 2023-08-04 jrmu ;; about the language level of this file in a form that our tools can easily process.
 3 12687dd9 2023-08-04 jrmu #reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname |27.2|) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp") (lib "gui.ss" "teachpack" "htdp")))))
 4 12687dd9 2023-08-04 jrmu Exercise 27.2.1.   Determine what the list-of-lines representation for empty, (list 'NL), and (list 'NL 'NL) should be. Why are these examples important test cases?
 5 12687dd9 2023-08-04 jrmu 
 6 12687dd9 2023-08-04 jrmu A file is either
 7 12687dd9 2023-08-04 jrmu 1. empty or
 8 12687dd9 2023-08-04 jrmu 2. (cons s f)
 9 12687dd9 2023-08-04 jrmu where s is a symbol and f is a file.
10 12687dd9 2023-08-04 jrmu