1 ;; The first three lines of this file were inserted by DrScheme. They record metadata
2 ;; about the language level of this file in a form that our tools can easily process.
3 #reader(lib "htdp-intermediate-reader.ss" "lang")((modname 16.2.3) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp") (lib "arrow.ss" "teachpack" "htdp")))))
4 A directory (dir) is a structure
5 (make-dir name content) where name is a symbol
6 and content is a list-of-files-and-directories (LOFD).
7 
8 A list-of-files-and-directories (LOFD) is either
9 1. empty,
10 2. (cons file lofd)
11 3. (cons dir lofd),
12 where file is a symbol, dir is a directory,
13 and lofd is a LOFD (list-of-files-and-directories).