8.16
Racket Cheat Sheet
Primitives
Numbers
| Literals | integer 1 rational 1/2 complex 1+2i floating 3.14 double 6.02e+23 hex #x29 octal #o32 binary #b010101 |
| Arithmetic | +-*/quotientremaindermoduloadd1sub1maxminroundfloorceilingsqrtexptexplogsin...atan |
| Compare | =<<=>>= |
| Bitwise | bitwise-iorbitwise-andbitwise-xorbitwise-notarithmetic-shiftinteger-length |
| Format | number->stringstring->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-stringstringstring-appendbuild-stringstring-join |
| Observe | string-lengthstring-refsubstringstring-splitin-string |
| Modify | string-downcasestring-upcasestring-trim |
| Test | string?string=?string<=?string-ci<=? |
| Regexp | #rx"a|b"#rx"^c(a|d)+r$"regexp-quoteregexp-matchregexp-splitregexp-replaceregexp-replace* |
| Match Pattern | (?string?s)"Banana?" |
Bytes
| Literals | #"rawbytes\0" |
| Create | make-bytesbytes |
| Numbers | integer->integer-bytesreal->floating-point-bytes |
| Observe | bytes-lengthbytes-refsubbytesin-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#fnotequal? |
| Characters | #\a#\tab#\λchar?char->integerinteger->charchar<=?...char-alphabetic?... |
| Symbols | 'Racketsymbol?eq?string->symbolgensym |
| Boxes | box?boxunboxset-box!box-cas! |
| Procedures | procedure?applycomposecompose1keyword-applyprocedure-renameprocedure-aritycurryarity-includes? |
| Void | void?void |
| Undefined | undefined |
Data
Lists
| Create | emptylistlist*build-listfor/list |
| Observe | empty?list?pair?lengthlist-refmembercountargminargmax |
| Use | appendreversemapandmapormapfoldrin-list |
| Modify | filterremove...sorttakedropsplit-atpartitionremove-duplicatesshuffle |
| Match Pattern | (listabc)(list*abmore)(listtopmore...) |
Immutable Hash
| Create | hashhasheq |
| Observe | hash?hash-refhash-has-key?hash-countin-hashin-hash-keysin-hash-values |
| Modify | hash-sethash-updatehash-remove |
Vector
| Create | build-vectorvectormake-vectorlist->vector |
| Observe | vector?vector-lengthvector-refin-vector |
| Modify | vector-set!vector-fill!vector-copy!vector-map! |
| Match Pattern | (vectorxyz)(vectorxycalabi–yau...) |
Streams
| Create | streamstream*empty-stream |
| Observe | stream-empty?stream-firststream-restin-stream |
Systems
Input/Output
Files
Miscellaneous
| Time | current-secondscurrent-inexact-millisecondsdate->stringdate-display-format |
| Command-Line Parsing | command-line |
| FFI | ffi-lib_uint32..._funmallocfree |
Networking
Security
| Custodians | make-custodiancustodian-shutdown-allcurrent-custodian |
| Sandboxes | make-evaluatormake-module-evaluator |
Concurrency
Parallelism
| Futures | futuretouchprocessor-countmake-fsemaphore... |
| Places | dynamic-placeplaceplace-waitplace-waitplace-channel... |
| Processes | subprocesssystem* |
Syntax (Beginner)
Basics
| Modules | (module+mainbody...) (module+testbody...) (requiremod-path)(provideid) |
| S-expressions | quote'(abc)quasiquoteunquote`(12,(+12)) |
| Procedure Applications | (fnarg1arg2) keyword args(fnarg1#:keyarg2) (applyfnarg1(listarg2)) |
| Procedures | (lambda(x)x)(λ(x)x) (λ(x[opt1])(+xopt)) (λ(x#:reqkey)(+xkey)) (λ(x#:opt[key1])(+xkey)) |
| Binding | (let([x1][y2])(+xy)) (let*([x1][x(+x1)])x) |
| Conditionals | (if(zero?x)0(/1x)) (cond[(even?x)0][(odd?x)1] [else"impossible!"]) andor |
| Definitions | (definex1) (define(fy)(+xy)) |
| Iteration | forfor/listfor* |
| Blocks | beginwhenunless |
| Require Sub-forms | prefix-inonly-inexcept-inrename-infor-syntaxfor-label... |
| Provide Sub-forms | all-defined-outall-from-outrename-out...contract-out |
Structures
| Definition | (structdillo(weightcolor)) |
| Create | (definedanny(dillo17.5'purple)) |
| Observe | (dillo?danny)(dillo-weightdanny)(dillo-colordanny) |
| Modify | (struct-copydillodanny([weight18.0])) |
| Match Pattern | (dillowc) |
Pattern Matching
| Basics | (matchvalue[patbody]...) |
| Definitions | (match-definepatvalue) |
| Patterns | (quotedatum)(listlvp...)(list-no-orderpat...)(vectorlvp...)(struct-idpat...)(regexprx-exprpat)(orpat...)(andpat...)(?exprpat...) |
Syntax (Intermediate)
Basics
| Mutation | set! |
| Exceptions | errorwith-handlersraiseexit |
| Promises | promise?delayforce |
| Continuations | let/cclet/ecdynamic-windcall-with-continuation-promptabort-current-continuationcall-with-composable-continuation |
| Parameters | make-parameterparameterize |
| External Files Needed at Runtime | define-runtime-path |
| Continuation Marks | continuation-markswith-continuation-markcontinuation-mark-set->list |
| Multiple Values | valueslet-valuesdefine-valuescall-with-values |
Contracts
| Basics | any/cor/cand/cfalse/cinteger-invector/clistoflist/c... |
| Functions | ->->*->i |
| Application | contract-outrecontract-outwith-contractdefine/contract |
Iteration
| Sequences | in-rangein-naturalsin-listin-vectorin-portin-linesin-hashin-hash-keysin-hash-valuesin-directoryin-cyclestop-beforestop-afterin-stream |
| Generators | generatoryieldin-generator |
Structures
| Sub-structures | (struct2d(xy))(struct3d2d(z))(2d-x(3d123)) |
| Mutation | (structmonster(type[hp#:mutable]))(definehealie(monster'slime10))(set-monster-hp!healie0) |
| Transparency | (structcash($¢)#:transparent)(struct->vector(cash595)) |
| Printing | (structnickname[nv]#:methodsgen:custom-write[(define(write-procnnpmode)(fprintfp(nickname-nnn)))])(displayln(nickname"evens"(in-range01002))) |
| Serialization | (structtxn(whowhatwhere)#:prefab)(write(txn"Mustard""Spatula""Observatory")) |
Generics
| Definition | define-generics |
| Instantiation | (structeven-set()#:methodsgen:set[(define(set-member?sti)(even?i))]) |
Classes
| Definition | interfaceclass* |
| Instantiation | make-objectnewinstantiate |
| Methods | sendsend/applysend/keyword-applysend*send+ |
| Fields | get-fieldset-field! |
| Mixins | mixin |
| Traits | traittrait-sumtrait-excludetrait-rename... |
| Contracts | class/cinstanceof/cis-a?/cimplementation?/csubclass?/c |
Syntactic Abstractions
| Definition | define-syntaxdefine-simple-macrobegin-for-syntaxfor-syntax |
| Templates | syntaxsyntax/locwith-syntax |
| Parsing ()-Syntax | syntax-parsedefine-syntax-classpattern |
| Syntax Objects | syntax-sourcesyntax-line...syntax->datumdatum->syntaxgenerate-temporariesformat-id |
| Transformers | make-set!-transformermake-rename-transformerlocal-expandsyntax-local-valuesyntax-local-namesyntax-local-lift-expression... |
| Syntax Parameters | define-syntax-parametersyntax-parameterizesyntax-parameter-value |
| Parsing Raw Syntax | lexerparsercfg-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 | slidestandard-fishcode |
