Racket Cheat Sheet

Racket Cheat Sheet

来源  http://docs.racket-lang.org/racket-cheat/index.html?q=Racket%20Cheat%20Sheet

Essentials

Sites	main download docs git
Community	packages users@ dev@ irc slack twitter
Running	Put #lang racket "Hello, world!" in hello.rkt and run racket hello.rkt

Primitives

Numbers

Literals	integer 1 rational  1/2  complex 1+2ifloating 3.14 double 6.02e+23 hex #x29 octal #o32 binary #b010101
Arithmetic	+ - * / quotient remaindermodulo add1 sub1 max min roundfloor ceiling sqrt expt exp logsin ... atan
Compare	= < <= > >=
Bitwise	bitwise-ior bitwise-andbitwise-xor bitwise-notarithmetic-shift integer-length
Format	number->string string->numberreal->decimal-string
Test	number? complex? ... exact-nonnegative-integer? ... zero?positive? negative? even? odd?exact? inexact?
Misc	random
Match Pattern	(? number? n) 42

Strings

Literals	"Racket" quoting "a \" approaches!"unicode "λx:(μα.α→α).xx"
Create	make-string string string-appendbuild-string string-join
Observe	string-length string-refsubstring string-split in-string
Modify	string-downcase string-upcasestring-trim
Test	string? string=? string<=?string-ci<=?
Regexp	#rx"a|b" #rx"^c(a|d)+r$" regexp-quote regexp-match regexp-splitregexp-replace regexp-replace*
Match Pattern	(? string? s) "Banana?"

Bytes

Literals	#"rawbytes\0"
Create	make-bytes bytes
Numbers	integer->integer-bytes real->floating-point-bytes
Observe	bytes-length bytes-refsubbytes in-bytes
Modify	bytes-set! bytes-copy! bytes-fill!
Conversion	bytes->string/utf-8  string->bytes/utf-8
Test	bytes? bytes=?
Match Pattern	(? bytes? b) #"0xDEADBEEF"

Other

Booleans	#t #f not equal?
Characters	#\a #\tab #\λ char? char->integer integer->char char<=?... char-alphabetic? ...
Symbols	'Racket symbol? eq? string->symbol gensym
Boxes	box? box unbox set-box! box-cas!
Procedures	procedure? apply composecompose1 keyword-applyprocedure-rename procedure-arity curry arity-includes?
Void	void? void
Undefined	undefined

Data

Lists

Create	empty list list* build-listfor/list
Observe	empty? list? pair? length list-ref member count argmin argmax
Use	append reverse map andmap ormapfoldr in-list
Modify	filter remove ... sort take dropsplit-at partition remove-duplicates shuffle
Match Pattern	(list a b c) (list* a b more)(list top more ...)

Immutable Hash

Create	hash hasheq
Observe	hash? hash-ref hash-has-key?hash-count in-hash in-hash-keysin-hash-values
Modify	hash-set hash-update hash-remove

Vector

Create	build-vector vector make-vectorlist->vector
Observe	vector? vector-length vector-refin-vector
Modify	vector-set! vector-fill! vector-copy! vector-map!
Match Pattern	(vector x y z) (vector x ycalabi–yau ...)

Streams

Create	stream stream* empty-stream
Observe	stream-empty? stream-firststream-rest in-stream

Mutable Hash

Create	make-hash make-hasheq
Observe	hash? hash-ref hash-has-key?hash-count in-hash in-hash-keysin-hash-values
Modify	hash-set! hash-ref! hash-update!hash-remove!

Systems

Input/Output

Formatting	~a ~v ~s ~e ~r pretty-format
Input	read read-bytes peek-byte
Output	write write-bytes displaydisplayln pretty-print
Ports and Files	with-input-from-file with-output-to-file flush-outputfile-position make-pipe with-output-to-string with-input-from-string port->bytes port->lines ...

Files

Paths	build-path bytes->path path->bytespath-replace-suffix ...
Files	file-exists? rename-file-or-directory copy-directory/filescurrent-directory make-directorydelete-directory/files directory-list filesystem-change-evt file->bytes file->lines make-temporary-file

Miscellaneous

Time	current-seconds current-inexact-milliseconds date->string date-display-format
Command-Line Parsing	command-line
FFI	ffi-lib _uint32 ... _fun mallocfree

Networking

TCP	tcp-listen tcp-connect tcp-accept tcp-close
HTTP	http-conn http-conn-open! http-conn-send! http-conn-recv!http-conn-sendrecv! http-sendrecv
URLs	string->url url->string url-query
Email	smtp-send-message imap-connect...
JSON	write-json read-json
XML	read-xml write-xml write-xexpr
Databases	postgresql-connect mysql-connect sqlite3-connect query-exec query-rows prepare start-transaction ...

Security

Custodians	make-custodian custodian-shutdown-all current-custodian
Sandboxes	make-evaluator make-module-evaluator

Concurrency

Threads	thread kill-thread thread-waitmake-thread-group
Events	sync choice-evt wrap-evthandle-evt alarm-evt ...
Channels	make-channel channel-getchannel-put
Semaphores	make-semaphore semaphore-postsemaphore-wait
Async Channels	make-async-channel async-channel-get async-channel-put

Parallelism

Futures	future touch processor-countmake-fsemaphore ...
Places	dynamic-place place place-waitplace-wait place-channel ...
Processes	subprocess system*

Syntax (Beginner)

Basics

Modules	(module+ main body ...)  (module+ test body ...)  (require mod-path) (provideid)
S-expressions	quote '(a b c) quasiquoteunquote `(1 2 ,(+ 1 2))
Procedure Applications	(fn arg1 arg2)  keyword args (fn arg1 #:keyarg2)  (apply fn arg1 (list arg2))
Procedures	(lambda (x) x) (λ (x) x)  (λ (x [opt 1]) (+ x opt))  (λ (x #:req key) (+ x key))  (λ (x #:opt [key 1]) (+ xkey))
Binding	(let ([x 1] [y 2]) (+ x y))  (let* ([x 1] [x (+ x 1)]) x)
Conditionals	(if (zero? x) 0 (/ 1 x))  (cond [(even? x) 0] [(odd? x)1]        [else "impossible!"])  and or
Definitions	(define x 1)  (define (f y) (+ x y))
Iteration	for for/list for*
Blocks	begin when unless
Require Sub-forms	prefix-in only-in except-inrename-in for-syntax for-label ...
Provide Sub-forms	all-defined-out all-from-outrename-out ... contract-out

Structures

Definition	(struct dillo (weight color))
Create	(define danny (dillo 17.5'purple))
Observe	(dillo? danny) (dillo-weightdanny) (dillo-color danny)
Modify	(struct-copy dillo danny([weight 18.0]))
Match Pattern	(dillo w c)

Pattern Matching

Basics	(match value [pat body] ...)
Definitions	(match-define pat value)
Patterns	(quote datum) (list lvp ...)(list-no-order pat ...) (vectorlvp ...) (struct-id pat ...)(regexp rx-expr pat) (or pat...) (and pat ...) (? expr pat...)

Syntax (Intermediate)

Basics

Mutation	set!
Exceptions	error with-handlers raiseexit
Promises	promise? delay force
Continuations	let/cc let/ec dynamic-windcall-with-continuation-prompt abort-current-continuation call-with-composable-continuation
Parameters	make-parameter parameterize
External Files Needed at Runtime	define-runtime-path
Continuation Marks	continuation-marks with-continuation-markcontinuation-mark-set->list
Multiple Values	values let-values define-values call-with-values

Contracts

Basics	any/c or/c and/c false/cinteger-in vector/c listoflist/c ...
Functions	-> ->* ->i
Application	contract-out recontract-outwith-contract define/contract

Iteration

Sequences	in-range in-naturals in-listin-vector in-port in-lines in-hash in-hash-keys in-hash-values in-directory in-cyclestop-before stop-after in-stream
Generators	generator yield in-generator

Structures

Sub-structures	(struct 2d (x y)) (struct 3d2d (z)) (2d-x (3d 1 2 3))
Mutation	(struct monster (type [hp#:mutable])) (define healie(monster 'slime 10)) (set-monster-hp! healie 0)
Transparency	(struct cash ($ ¢)#:transparent) (struct->vector (cash 5 95))
Printing	(struct nickname [n v]#:methods gen:custom-write[(define (write-proc nn pmode) (fprintf p (nickname-nnn)))]) (displayln (nickname"evens" (in-range 0 100 2)))
Serialization	(struct txn (who what where)#:prefab) (write (txn"Mustard" "Spatula""Observatory"))

Generics

Definition	define-generics
Instantiation	(struct even-set () #:methodsgen:set [(define (set-member?st i) (even? i))])

Classes

Definition	interface class*
Instantiation	make-object new instantiate
Methods	send send/apply send/keyword-apply send* send+
Fields	get-field set-field!
Mixins	mixin
Traits	trait trait-sum trait-excludetrait-rename ...
Contracts	class/c instanceof/c is-a?/cimplementation?/c subclass?/c

Syntactic Abstractions

Definition	define-syntax define-simple-macro begin-for-syntax for-syntax
Templates	syntax syntax/loc with-syntax
Parsing ()-Syntax	syntax-parse define-syntax-class pattern
Syntax Objects	syntax-source syntax-line ...syntax->datum datum->syntaxgenerate-temporaries format-id
Transformers	make-set!-transformer make-rename-transformer local-expand syntax-local-valuesyntax-local-name syntax-local-lift-expression ...
Syntax Parameters	define-syntax-parametersyntax-parameterize syntax-parameter-value
Parsing Raw Syntax	lexer parser cfg-parser

Tools

Packages

Inspection	raco pkg show
Finding	pkgs.racket-lang.org
Installing	raco pkg install
Updating	raco pkg update
Removing	raco pkg remove

Miscellaneous

Compiling	raco make program.rkt
Testing	raco test program.rkt a-directory
Building Executables	raco exe program.rkt
Extending DrRacket	drracket:language:simple-module-based-language->module-based-language-mixin
Slides	slide standard-fish code

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