From 8715a946ec60184cc9270affbf28a7302db31a3e Mon Sep 17 00:00:00 2001
From: daniel watson <ozzloy@gmail.com>
Date: Thu, 4 Aug 2016 09:12:22 -0700
Subject: [PATCH] take note up to first and rest functions

---
 notes.org | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 notes.org

diff --git a/notes.org b/notes.org
new file mode 100644
index 0000000..ebc40bf
--- /dev/null
+++ b/notes.org
@@ -0,0 +1,54 @@
+* form
+  * "(function element0 ...)"
+* building blocks of racket semantics
+** booleans
+   * "(zero? 1)" "(zero? (sub1 1))"
+** symbols
+   * a-z+-/*=<>?!_^
+   * (symbol=? 'foo 'FoO) true or false?
+** numbers
+   * "(expt 53 53)" "(= (/ 4 6) 2/3 (/ 2 3))" "(= (/ 4.0 6) 0.6666666666666666)"
+   * numbers like 4.0 are floating point numbers
+   * irrational numbers
+** strings
+   * "tutti frutti"
+   * (= (string-append "tutti" "frutti") "tuttifrutti")
+   * (= (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)))
+    * 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)
+*** lists and list functions
+    * (= '() empty (list))
+**** cons function
+     * (= (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 '())))
+          '(pork beef chicken))
+**** list function
+     * (= (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)
+     * 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))
+     * all lists are made of cons cells
+     * (= (first '((peas carrots tomatoes) (pork beef chicken)))
+          (peas carrots tomatoes))
+     * (= (rest '(peas carrots tomatoes)) '(carrots tomatoes))
+     * (= (rest (first '((peas carrots tomatoes) (pork beef chicken))))
+          '(carrots tomatoes))
+     * second third ... tenth built-in
-- 
2.30.2