replace = with equal? where necessary

diff --git a/notes.org b/notes.org
index ebc40bf4477f44d96fecf242b109f6e60a97f49e..10afb31cbf6a3135d171cb5aa31d90debfd40413 100644 (file)
--- a/notes.org
+++ b/notes.org
@@ -12,43 +12,54 @@
    * irrational numbers
 ** strings
    * "tutti frutti"
-   * (= (string-append "tutti" "frutti") "tuttifrutti")
-   * (= (string-append "tutti" " " "frutti") "tutti frutti")
+   * (equal? (string-append "tutti" "frutti") "tuttifrutti")
+   * (equal?(string-append "tutti" " " "frutti") "tutti frutti")
    * substring, string-ref, string=?
 ** lists
    * super duper important in racket
 *** cons cells
-    * (= (list 1 2) (cons 2 (cons 3 empty)))
+    * (equal?(list 1 2) (cons 2 (cons 3 empty)))
     * same as linked lists in other languages
 **** functions for cons cells
-     * (= (cons 1 2) '(1 . 2))
-     * (define cell (cons 'a 'b)) (= (car cell) 'a) (= (cdr cell) 'b)
+     * (equal?(cons 1 2) '(1 . 2))
+     * (define cell (cons 'a 'b)) (equal?(car cell) 'a) (equal?(cdr cell) 'b)
 *** lists and list functions
-    * (= '() empty (list))
+    * (equal?'() empty (list))
 **** cons function
-     * (= (cons 'chicken empty) '(chicken))
+     * (equal?(cons 'chicken empty) '(chicken))
      * empty is used to terminate lists in racket, so '(chicken) has
        an implicit empty
      * what do you get when you add a chicken to an empty list? a list with
        a chicken in it
-     * (= (cons 'pork '(beef chicken)) '(pork beef chicken))
-     * (= (cons 'beef (cons 'chicken '())) '(beef chicken))
-     * (= (cons 'pork (cons 'beef (cons 'chicken '())))
+     * (equal?(cons 'pork '(beef chicken)) '(pork beef chicken))
+     * (equal?(cons 'beef (cons 'chicken '())) '(beef chicken))
+     * (equal?(cons 'pork (cons 'beef (cons 'chicken '())))
           '(pork beef chicken))
 **** list function
-     * (= (list 'pork 'beef 'chicken) '(pork beef chicken))
+     * (equal?(list 'pork 'beef 'chicken) '(pork beef chicken))
 **** first and rest functions
-     * (= (first (cons 'pork (cons 'beef (cons 'chicken empty)))) 'pork)
-     * (= (rest (list 'pork 'beef 'chicken)) '(beef chicken))
-     * (= (first (rest ('pork beef chicken))) 'beef)
+     * (equal?(first (cons 'pork (cons 'beef (cons 'chicken empty)))) 'pork)
+     * (equal?(rest (list 'pork 'beef 'chicken)) '(beef chicken))
+     * (equal?(first (rest ('pork beef chicken))) 'beef)
      * how do you get the third item?
      * what happens when you try to get the fourth item?
 **** nested lists
-     * (= (list 'cat (list 'duck 'bat) 'ant) '(cat (duck bat) ant))
+     * (equal?(list 'cat (list 'duck 'bat) 'ant) '(cat (duck bat) ant))
      * all lists are made of cons cells
-     * (= (first '((peas carrots tomatoes) (pork beef chicken)))
+     * (equal?(first '((peas carrots tomatoes) (pork beef chicken)))
           (peas carrots tomatoes))
-     * (= (rest '(peas carrots tomatoes)) '(carrots tomatoes))
-     * (= (rest (first '((peas carrots tomatoes) (pork beef chicken))))
+     * (equal?(rest '(peas carrots tomatoes)) '(carrots tomatoes))
+     * (equal?(rest (first '((peas carrots tomatoes) (pork beef chicken))))
           '(carrots tomatoes))
      * second third ... tenth built-in
+** structures
+   structures group things together, like lists. structures group a
+   fixed number of items, unlike lists.
+   example: student has name ID dorm.
+*** structure basics
+    * "(struct student (name id# dorm))"
+      this defines a structure, but doesn't actually create one.
+    * "(define freshman1 (student 'Joe 1234 'NewHall))"
+      this creates a structure
+    * fields: name, id#, dorm
+    * (equal? (student-name freshman1) 'Joe)