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added struct, quote

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Manu 2013-07-14 23:59:16 +12:00
parent 930d12e98f
commit 150b232b9b
1 changed files with 83 additions and 28 deletions
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racket.html.markdown
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@ -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>
(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") ; => #<procedure>
; (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]))
; Sequences
(fizzbuzz? 15) ; => 'fizzbuzz
(fizzbuzz? 37) ; => #f
;;; 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
(provide print-cake) ;; function exported by the module
(module cake racket/base ; define a new module 'cake' based on racket/base
(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))