diff --git a/racket.html.markdown b/racket.html.markdown
index 8cc5ac24..fed3587c 100644
--- a/racket.html.markdown
+++ b/racket.html.markdown
@@ -11,12 +11,6 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
```racket
#lang racket ; defines the language we are using
-; TODO:
-; quote
-; structs
-; control flow (pattern-matching, loops, sequences)
-
-
; Single line comments start with a semicolon
#| Multiline strings can be written
using three "'s, and are often used
@@ -27,7 +21,7 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
;; 1. Primitive Datatypes and Operators
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; Numbers
+;;; Numbers
9999999999999999999999 ; integers
3.14 ; reals
6.02e+23
@@ -36,8 +30,10 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
; Function application is written (f x y z ...)
; where f is a function and x, y, z, ... are operands
-
-; Here are a few arithmetic operators
+; If you want to create a literal list of data, use ' to stop it from
+; being evaluated
+'(+ 1 2) ; => (+ 1 2)
+; Now, some arithmetic operations
(+ 1 1) ; => 2
(- 8 1) ; => 7
(* 10 2) ; => 20
@@ -48,7 +44,7 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
(exact->inexact 1/3) ; => 0.3333333333333333
(+ 1+2i 2-3i) ; => 3-1i
-; Booleans
+;;; Booleans
#t ; for true
#f ; for false
(not #t) ; => #f
@@ -57,12 +53,12 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
(= 1 1.0) ; => #t
(= 2 1) ; => #f
-; Characters
+;;; Characters
#\A ; => #\A
#\λ ; => #\λ
#\u03BB ; => #\λ
-; Strings are fixed-length array of characters.
+;;; Strings are fixed-length array of characters.
"Hello, world!"
"Benjamin \"Bugsy\" Siegel" ; backslash is an escaping character
"λx:(μα.α→α).xx" ; any Unicode character can appear in a string constant
@@ -83,7 +79,7 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
;; 2. Variables
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; You can create a variable using define
-; a variable name can use any characters except: () [] {} " , ' ` ; # | \
+; a variable name can use any character except: ()[]{}",'`;#|\
(define some-var 5)
some-var ; => 5
@@ -100,14 +96,29 @@ some-var ; => 6
me) ; => "Bob"
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-;; 3. Collections
+;; 3. Structs and Collections
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; Structs
+(struct dog (name breed age))
+(define my-pet
+ (dog "lassie" "collie" 5))
+my-pet ; => #
+(dog? my-pet) ; => #t
+(dog-name my-pet) ; => "lassie"
+
+; Pairs
+; "cons" constructs pairs, "car" and "cdr" extract the first
+; and second elements
+(cons 1 2) ; => '(1 . 2)
+(car (cons 1 2)) ; => 1
+(cdr (cons 1 2)) ; => 2
+
; Lists are linked-list data structures
-'(1 2 3)
+'(1 2 3) ; => '(1 2 3)
; Vectors are fixed-length arrays
-#(1 2 3)
+#(1 2 3) ; => '#(1 2 3)
; Use "cons" to add an item to the beginning of a list
(cons 4 '(1 2 3)) ; => (4 1 2 3)
@@ -167,8 +178,8 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
;; 3. Functions
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; Use lambda to create new functions. A function always returns
-; its last statement.
+; Use lambda to create new functions.
+; A function always returns its last statement.
(lambda () "Hello World") ; => #
; (You need extra parens to call it)
@@ -210,7 +221,8 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
;; 4. Control Flow
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; Conditionals
+;;; Conditionals
+
(if #t ; test expression
"this is true" ; then expression
"this is false" ; else expression
@@ -222,20 +234,61 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
'yep
'nope) ; => 'yep
-
; "cond" chains a series of tests to select a result
(cond
[(> 2 2) (error "wrong!")]
[(< 2 2) (error "wrong again!")]
[else 'ok]) ; => 'ok
-; Pattern matching
+;;; Pattern Matching
-; Loops
+(define (fizzbuzz? n)
+ (match (list (remainder n 3) (remainder n 5))
+ [(list 0 0) 'fizzbuzz]
+ [(list 0 _) 'fizz]
+ [(list _ 0) 'buzz]
+ [_ #f]))
+
+(fizzbuzz? 15) ; => 'fizzbuzz
+(fizzbuzz? 37) ; => #f
-; Sequences
+;;; Loops
+
+(define (loop i)
+ (when (< i 10)
+ (printf "i:~a~n" i)
+ (loop (add1 i))))
+
+(loop 5) ; => i:5 i:6 ...
+
+(let loop ((i 0))
+ (when (< i 10)
+ (printf "i:~a~n" i)
+ (loop (add1 i)))) ; => i:0 i:1 ...
+
+
+;;; Sequences
+
+; "for" allows iteration over sequences:
+; lists, vectors, strings, sets, hash tables, etc...
+(for ([i (in-list '(l i s t))])
+ (displayln i))
+
+(for ([i (in-vector #(v e c t o r))])
+ (displayln i))
+
+(for ([i (in-string "string")])
+ (displayln i))
+
+(for ([i (in-set (set 'x 'y 'z))])
+ (displayln i))
+
+(for ([(k v) (in-hash (hash 'a 1 'b 2 'c 3 ))])
+ (printf "key:~a value:~a ~n" k v))
+
+
+;;; Exceptions
-; Exceptions
; To catch an exception, use the "with-handlers" form
; To throw an exception use "raise"
(with-handlers
@@ -246,11 +299,12 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; 5. Modules
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; Modules let you organize code into multiple files and reusable libraries.
-(module cake racket/base ;; define a new module 'cake' based on racket/base
+; Modules let you organize code into multiple files and reusable libraries
+
+(module cake racket/base ; define a new module 'cake' based on racket/base
- (provide print-cake) ;; function exported by the module
+ (provide print-cake) ; function exported by the module
(define (print-cake n)
(show " ~a " n #\.)
@@ -262,7 +316,7 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
(printf fmt (make-string n ch))
(newline)))
-;; Use "require" to import all functions from the module
+; Use "require" to import all functions from the module
(require 'cake)
(print-cake 3)
;(show "~a" 1 #\A) ; => error, "show" was not exported
@@ -302,6 +356,7 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; 7. Macros
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
; Macros let you extend the syntax of the language
(define-syntax-rule (unless test then else)
(if test else then))