From 4ad1441e839282f97fc3e2031f97a4adc552a707 Mon Sep 17 00:00:00 2001
From: Eli Barzilay <eli@barzilay.org>
Date: Tue, 16 Jul 2013 01:22:11 -0400
Subject: Normalize top comments to start with ";;".

Leave a single ";" for commented expressions and output indications.
---
 racket.html.markdown | 155 +++++++++++++++++++++++++--------------------------
 1 file changed, 77 insertions(+), 78 deletions(-)

(limited to 'racket.html.markdown')

diff --git a/racket.html.markdown b/racket.html.markdown
index 4b72591a..25b92f62 100644
--- a/racket.html.markdown
+++ b/racket.html.markdown
@@ -17,7 +17,7 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
 
 ;;; Comments
 
-; Single line comments start with a semicolon
+;; Single line comments start with a semicolon
 
 #| Block comments
    can span multiple lines and...
@@ -26,7 +26,7 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
     |#   
 |#
 
-; S-expression comments discard the following expression
+;; S-expression comments discard the following expression
 #; "this expression will be discarded" "2nd expression" ; => "2nd expression"
  
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -40,12 +40,12 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
 1/2                    ; rationals   
 1+2i                   ; complex numbers   
 
-; Function application is written (f x y z ...) 
-; where f is a function and x, y, z, ... are operands
-; If you want to create a literal list of data, use ' to stop it from
-; being evaluated
+;; Function application is written (f x y z ...) 
+;; where f is a function and x, y, z, ... are operands
+;; 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
+;; Now, some arithmetic operations
 (+ 1 1)  ; => 2
 (- 8 1)  ; => 7
 (* 10 2) ; => 20
@@ -73,34 +73,34 @@ Feedback is appreciated! You can reach me at [@th3rac25](http://twitter.com/th3r
 "Benjamin \"Bugsy\" Siegel" ; backslash is an escaping character
 "λx:(μα.α→α).xx" ; any Unicode character can appear in a string constant
 
-; Strings can be added too!
+;; Strings can be added too!
 (string-append "Hello " "world!") ; => "Hello world!"
 
-; A string can be treated like a list of characters
+;; A string can be treated like a list of characters
 (string-ref "Apple" 0) ; => #\A
 
-; format can be used to format strings:
+;; format can be used to format strings:
 (format "~a can be ~a" "strings" "formatted")
 
-; Printing is pretty easy
+;; Printing is pretty easy
 (printf "I'm Racket. Nice to meet you!\n")
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; 2. Variables
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
-; You can create a variable using define
-; a variable name can use any character except: ()[]{}",'`;#|\
+;; You can create a variable using define
+;; a variable name can use any character except: ()[]{}",'`;#|\
 (define some-var 5)
 some-var ; => 5
 
-; You can also use unicode characters
+;; You can also use unicode characters
 (define ⊆ subset?)
 (⊆ (set 3 2) (set 1 2 3)); => #t
 
-; Accessing a previously unassigned variable is an exception
-;x ; => x: undefined ...
+;; Accessing a previously unassigned variable is an exception
+; x ; => x: undefined ...
 
-; Local binding: me is bound to "Bob" only within (let ...)
+;; Local binding: me is bound to "Bob" only within (let ...)
 (let ([me "Bob"])
     "Alice"
     me) ; => "Bob"
@@ -109,7 +109,7 @@ some-var ; => 5
 ;; 3. Structs and Collections
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Structs
+;; Structs
 (struct dog (name breed age))
 (define my-pet 
   (dog "lassie" "collie" 5))
@@ -118,95 +118,95 @@ my-pet ; => #<dog>
 (dog-name my-pet) ; => "lassie"
 
 ;;; Pairs (immutable)
-; "cons" constructs pairs, "car" and "cdr" extract the first
-; and second elements
+;; "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
 
-; Lists are linked-list data structures
+;; Lists are linked-list data structures
 (list 1 2 3) ; => '(1 2 3)
 
-; Use "cons" to add an item to the beginning of a list
+;; Use "cons" to add an item to the beginning of a list
 (cons 4 '(1 2 3)) ; => (4 1 2 3)
 
-; Use "append" to add lists together
+;; Use "append" to add lists together
 (append '(1 2) '(3 4)) ; => (1 2 3 4)
 
 ;;; Vectors
 
-; Vectors are fixed-length arrays
+;; Vectors are fixed-length arrays
 #(1 2 3) ; => '#(1 2 3)
 
-; Use "vector-append" to add vectors together
+;; Use "vector-append" to add vectors together
 (vector-append #(1 2 3) #(4 5 6)) ; => #(1 2 3 4 5 6)
 
 ;;; Sets
 
-; create a set from a list
+;; create a set from a list
 (list->set '(1 2 3 1 2 3 3 2 1 3 2 1)) ; => (set 1 2 3)
 
-; Add a member with "set-add"
+;; Add a member with "set-add"
 (set-add (set 1 2 3) 4); => (set 1 2 3 4)
 
-; Remove one with "set-remove"
+;; Remove one with "set-remove"
 (set-remove (set 1 2 3) 1) ; => (set 2 3)
 
-; Test for existence with "set-member?"
+;; Test for existence with "set-member?"
 (set-member? (set 1 2 3) 1) ; => #t
 (set-member? (set 1 2 3) 4) ; => #f
 
 ;;; Hashes
 
-; Create an immutable hash table (There are also mutables ones)
+;; Create an immutable hash table (There are also mutables ones)
 (define m (hash 'a 1 'b 2 'c 3))
 
-; Retrieve a value
+;; Retrieve a value
 (hash-ref m 'a) ; => 1
 
-; Retrieving a non-present value is an exception
+;; Retrieving a non-present value is an exception
 ; (hash-ref m 'd) => no value found
 
-; You can provide a default value for missing keys
+;; You can provide a default value for missing keys
 (hash-ref m 'd 0) ; => 0
 
-; Use "hash-set" to extend a hash table
+;; Use "hash-set" to extend a hash table
 (define m2 (hash-set m 'd 4)) 
 m2 ; => '#hash((b . 2) (a . 1) (d . 4) (c . 3))
 
-; Remember, these hashes are immutable!
+;; Remember, these hashes are immutable!
 m ; => '#hash((b . 2) (a . 1) (c . 3))
 
-; Use "hash-remove" to remove keys
+;; Use "hash-remove" to remove keys
 (hash-remove m 'a) ; => '#hash((b . 2) (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") ; => #<procedure>
 
-; (You need extra parens to call it)
+;; (You need extra parens to call it)
 ((lambda () "Hello World")) ; => "Hello World"
 
-; Assign a function to a var
+;; Assign a function to a var
 (define hello-world (lambda () "Hello World"))
 (hello-world) ; => "Hello World"
 
-; You can shorten this to:
+;; You can shorten this to:
 (define (hello-world2) "Hello World")
 
-; The () is the list of arguments for the function.
+;; The () is the list of arguments for the function.
 (define hello 
   (lambda (name)
     (string-append "Hello " name)))
 (hello "Steve") ; => "Hello Steve"
 
-; You can have multi-variadic functions, too
+;; You can have multi-variadic functions, too
 (define hello2
   (case-lambda 
     [() "Hello World"]
@@ -214,12 +214,12 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 (hello2 "Jake") ; => "Hello Jake"
 (hello2) ; => "Hello World"
 
-; Functions can pack extra arguments up in a list
+;; Functions can pack extra arguments up in a list
 (define (count-args . args)
   (format "You passed ~a args: ~a" (length args) args))
 (count-args 1 2 3) ; => "You passed 3 args: (1 2 3)"
 
-; You can mix regular and packed arguments
+;; You can mix regular and packed arguments
 (define (hello-count name . args)
   (format "Hello ~a, you passed ~a extra args" name (length args)))
 (hello-count "Finn" 1 2 3)
@@ -229,16 +229,16 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 ;; 4. Equality
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; for numbers use "="
+;; for numbers use "="
 (= 3 3.0) ; => #t
 (= 2 1) ; => #f
 
-; for object identity use "eq?"
+;; for object identity use "eq?"
 (eq? 3 3) ; => #t
 (eq? 3 3.0) ; => #f
 (eq? (list 3) (list 3)) ; => #f
 
-; for collections use "equal?"
+;; for collections use "equal?"
 (equal? (list 'a 'b) (list 'a 'b)) ; => #t
 (equal? (list 'a 'b) (list 'b 'a)) ; => #f
 
@@ -253,13 +253,13 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
     "this is false"  ; else expression
     ) ; =>  "this is true"
 
-; In conditionals, all non-#f values are treated as true
+;; In conditionals, all non-#f values are treated as true
 (member "Groucho" '("Harpo" "Groucho" "Zeppo")) ; => '("Groucho" "Zeppo")
 (if (member "Groucho" '("Harpo" "Groucho" "Zeppo"))
       'yep
       'nope) ; => 'yep
 
-; "cond" chains a series of tests to select a result
+;; "cond" chains a series of tests to select a result
 (cond
    [(> 2 2) (error "wrong!")]
    [(< 2 2) (error "wrong again!")]
@@ -279,7 +279,7 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 
 ;;; Loops
 
-; looping can be done through recursion
+;; looping can be done through recursion
 (define (loop i)
   (when (< i 10)
     (printf "i:~a~n" i)
@@ -287,7 +287,7 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 
 (loop 5) ; => i:5 i:6 ... 
 
-; similarly, with a named let
+;; similarly, with a named let
 (let loop ((i 0))
   (when (< i 10)
     (printf "i:~a~n" i)
@@ -304,14 +304,14 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 (for/hash ([i '(1 2 3)])
     (values i (number->string i))) ; => '#hash((1 . "1") (2 . "2") (3 . "3"))
 
-; To combine iteration results, use "for/fold"
+;; To combine iteration results, use "for/fold"
 (for/fold ([sum 0]) ([i '(1 2 3 4)])
   (+ sum i)) ; => 10
 
 ;;; Sequences
 
-; "for" allows iteration over sequences: 
-; lists, vectors, strings, sets, hash tables, etc... 
+;; "for" allows iteration over sequences: 
+;; lists, vectors, strings, sets, hash tables, etc... 
 (for ([i (in-list '(l i s t))])
   (displayln i))
 
@@ -329,8 +329,8 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 
 ;;; Exceptions
 
-; To catch an exception, use the "with-handlers" form
-; To throw an exception use "raise"
+;; To catch an exception, use the "with-handlers" form
+;; To throw an exception use "raise"
 (with-handlers 
     ([(lambda (v) (equal? v "infinity"))   
       (lambda (exn) +inf.0)])
@@ -340,17 +340,17 @@ m ; => '#hash((b . 2) (a . 1) (c . 3))
 ;; 6. Mutation
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Use set! to assign a new value to an existing variable
+;; Use set! to assign a new value to an existing variable
 (define n 5)
 (set! n 6) 
 n ; => 6
 
-; Many Racket datatypes can be immutable or mutable 
-; (Pairs, Lists, Strings, Vectors, Hash Tables, etc...)
+;; Many Racket datatypes can be immutable or mutable 
+;; (Pairs, Lists, Strings, Vectors, Hash Tables, etc...)
 
-; Use "vector" to create a mutable vector
+;; Use "vector" to create a mutable vector
 (define vec (vector 2 2 3 4))
-; Use vector-set! to update a slot
+;; Use vector-set! to update a slot
 (vector-set! vec 0 1)
 vec ; => #(1 2 3 4)
 
@@ -358,7 +358,7 @@ vec ; => #(1 2 3 4)
 ;; 7. Modules
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Modules let you organize code into multiple files and reusable libraries
+;; Modules let you organize code into multiple files and reusable libraries
 
 (module cake racket/base ; define a new module 'cake' based on racket/base
   
@@ -374,16 +374,16 @@ vec ; => #(1 2 3 4)
     (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
+; (show "~a" 1 #\A) ; => error, "show" was not exported
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; 8. Classes and Objects
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Create a class fish%
+;; Create a class fish%
 (define fish%
   (class object% 
     (init size) ; initialization argument
@@ -395,11 +395,11 @@ vec ; => #(1 2 3 4)
     (define/public (grow amt) (set! current-size (+ amt current-size)))
     (define/public (eat other-fish) (grow (send other-fish get-size)))))
 
-; Create an instance of fish%
+;; Create an instance of fish%
 (define charlie 
   (new fish% [size 10]))
 
-; Use "send" to call an object's methods
+;; Use "send" to call an object's methods
 (send charlie grow 6)
 (send charlie get-size) ; => 16
  
@@ -407,9 +407,9 @@ vec ; => #(1 2 3 4)
 ;; 9. Macros
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Macros let you extend the syntax of the language
+;; Macros let you extend the syntax of the language
 
-; Let's add a while loop
+;; Let's add a while loop
 (define-syntax-rule (while condition body ...)
   (let loop ()
     (when condition
@@ -421,7 +421,7 @@ vec ; => #(1 2 3 4)
     (displayln i)
     (set! i (add1 i))))
 
-; Macros are hygienic, you cannot clobber existing variables!   
+;; Macros are hygienic, you cannot clobber existing variables!   
 (define-syntax-rule (swap x y)
   (begin
     (define tmp x) 
@@ -438,7 +438,7 @@ vec ; => #(1 2 3 4)
 ;; 10. Contracts
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-; Contracts impose constraints on values exported from modules
+;; Contracts impose constraints on values exported from modules
 
 (module bank-account racket
   (provide (contract-out
@@ -455,14 +455,13 @@ vec ; => #(1 2 3 4)
 
 (balance) ; => 5
 
-; Any client that attempt to deposit a non-positive amount, will be blamed
-; (deposit -5) ; => deposit: contract violation 
-; expected: positive?
-; given: -5 
-; more details....
+;; Any client that attempt to deposit a non-positive amount, will be blamed
+;; (deposit -5) ; => deposit: contract violation 
+;; expected: positive?
+;; given: -5 
+;; more details....
 ```
 
 ## Further Reading
 
 Still up for more? Try [Quick: An Introduction to Racket with Pictures](http://docs.racket-lang.org/quick/)
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