Every module in the standard library, what it is for, and where the book
covers it. All of them are reachable with a bare import, with no package
manager and no dependency to add.
Each module’s source is in libs/, and every public function in it carries
a doc block stating its parameters, its defaults and its edge cases.
Module What it is for Book
jsonencode, decode, read and write JSON 13 yamlparse YAML, with anchors, tags and multi-document streams 13 tomlparse and write TOML, and edit one without disturbing its layout 13 csvread and write CSV, with dialect detection 13 structpack and unpack binary layouts 10 base64Base64 encode and decode 10 convertbase, hex, binary, octal and unicode conversions 13 compressdeflate, zlib, gzip, zstd, lz4, bzip2, brotli, tar, zip, checksums 10
Module What it is for Book
htmla WHATWG-conformant parser, a DOM and CSS selectors 13 wiretemplating, with directives as HTML attributes 14 urlparse, build and percent-encode URLs 13 mimedetect a media type from a name or from content 13 colorsANSI terminal colour, with graceful degradation 13
Module What it is for Book
datedates, times, formatting, parsing and IANA time zones 13
Module What it is for Book
hashdigests and HMACs, plus PBKDF2 10 bcryptpassword hashing 13 cryptoRSA signing and HKDF 13 uuidUUID versions 1, 3, 4, 5, 6, 7 and 8 13 jwtsign, verify and decode JSON Web Tokens, with JWKS 13
Module What it is for Book
validatea fluent schema builder 13 typeschecked coercion between types 13 setan ordered set with the usual algebra 13 enumnamed constants from a list or a dictionary 13 arraytyped fixed-width numeric arrays, Int8 through Double 13
Module What it is for Book
osprocesses, filesystem, paths, environment, signals 9 enva .env file into the environment, and typed values back out 19 iostandard streams, the terminal, and in-memory files 9 , 10 statthe S_IS* predicates over a file mode 13 argsa command-line parser with subcommands and --help 20 loglevelled, structured logging with pluggable transports 13 isolateOS-thread concurrency, channels and broadcasts 11 fficalling C and Rust libraries, callbacks, and linking static libraries 26
Module What it is for Book
testsuites, matchers, test doubles, snapshots and reports 23
Module What it is for Book
sqlone contract for every relational database, with SQLite, PostgreSQL and MySQL adapters 17
Module What it is for Book
mailmessages, SMTP, IMAP and POP3, both server ends, and DKIM 18
Module What it is for Book
netTCP, UDP, unix sockets, TLS, DTLS, addresses and polling 12 httpan HTTP/1.1 and HTTP/2 client and server 15 rpcJSON-RPC 2.0 over HTTP, WebSockets, sockets and streams, both ends 28
Module What it is for Book
imaginedecode, draw, filter and encode images 16
Module What it is for Book
maththe mathematical constants 4
Module What it is for Book
zurilexing, parsing, compiling and runtime reflection 21
Most of the larger modules are packages: a directory whose index.zu
re-exports what its parts make public. import http reaches almost all of
http without naming a submodule. Import a submodule directly when you
want only that part of it, or when a name would otherwise collide.
One module per element width, each exporting a single class.
Submodule Class Element
array.int8Int8Arraysigned 8-bit array.uint8UInt8Arrayunsigned 8-bit array.int16Int16Arraysigned 16-bit array.uint16UInt16Arrayunsigned 16-bit array.int32Int32Arraysigned 32-bit array.uint32UInt32Arrayunsigned 32-bit array.int64Int64Arraysigned 64-bit array.uint64UInt64Arrayunsigned 64-bit array.floatFloatArray32-bit float array.doubleDoubleArray64-bit float
Submodule What it is for
compress.deflateraw DEFLATE streams compress.zlibDEFLATE with a zlib header compress.gzipDEFLATE with a gzip header and trailer compress.zstdZstandard, levels 1 to 22 compress.lz4LZ4, block and frame formats compress.bzip2bzip2 compress.brotliBrotli compress.tarreading and writing TAR archives compress.zipreading and writing ZIP archives compress.checksumCRC32, CRC32C, Adler-32
Submodule What it is for
ffi.errorsevery error the module raises, under FfiError ffi.typesType, and the struct, union and enum buildersffi.pointerPointer: native memory and access through itffi.libraryLibrary: a loaded shared libraryffi.declareDeclarations: C and Rust source read into types and signaturesffi.callbackCallback: a Zuri function behind a C function pointer
Submodule What it is for
html.tokenizerthe WHATWG tokenizer: text in, tokens out html.parsertree construction: tokens in, a document out html.nodethe document tree and everything you can do to it html.selectorfinding nodes with CSS selectors html.serializewriting a document back out, minified or pretty html.entitiesnamed character references, both directions html.elementsthe element tables tree construction consults html.namespacesthe five namespace URIs the parser deals in
Submodule What it is for
http.clientHttpClient, the request sidehttp.serverHttpServer, the listening sidehttp.workerserving across several isolates http.routermatching a method and path to a handler http.middlewareCORS, access logging, security headers, and the rest http.requestthe request object handlers receive http.responsethe response object handlers return http.headersHeaders, with the field-name rules of RFC 9110http.cookiesCookie and CookieJarhttp.sessionserver-side sessions, and the stores that keep them http.session.sqlkeeping sessions in a relational database http.bodyreading and writing message bodies http.multipartmultipart/form-data, including file uploadshttp.filesserving files from disk, with ranges and caching http.streamchunked and streaming transfers http.sseserver-sent events http.websocketthe WebSocket protocol http.proxyforwarding requests to another server http.negotiateparsing Accept-style headers http.statusthe IANA status codes and their reason phrases http.h1the HTTP/1.1 wire format http.errorsthe module’s error hierarchy
Submodule What it is for
imagine.imageImage, the pixel buffer everything else operates onimagine.canvasdrawing: lines, shapes, fills, text imagine.colorColor, and conversion between colour spacesimagine.filtersblur, sharpen, convolution, and the rest imagine.fontloading and measuring fonts imagine.strokefontthe built-in stroke font, with no file to load imagine.formatsdecoding and encoding PNG, JPEG, GIF, WebP and more imagine.animationmulti-frame images imagine.constantsthe named constants the module understands imagine.errorsthe module’s error hierarchy
Submodule What it is for
io.bytesioBytesIO, a file-shaped object backed by memoryio.ttyterminal control: raw mode, size, cursor
Submodule What it is for
isolate.channelbounded multi-producer, multi-consumer queues isolate.broadcastone-to-many publish and subscribe isolate.errorIsolateError
Submodule What it is for
jwt.coreencode(), decode(), sign(), verify()jwt.signerSigner, a reusable configured signerjwt.verifierVerifier, a reusable configured verifierjwt.tokenthe Token object a complete decode returns jwt.jwksresolving a signing key from a JSON Web Key Set jwt.codecalgorithm identifiers and the low-level encoding jwt.errorsthe module’s error hierarchy
Submodule What it is for
log.loggerthe module-level info(), warn(), error() and friends log.levelthe LogLevel enum and the default level log.transportTransport, the base class every sink extendslog.consoleConsoleTransport, the defaultlog.fileFileTransport, with size-based rotationlog.dispatchconfiguring which transports receive what
Submodule What it is for
net.tcpTcpSocket and TcpStreamnet.udpUdpSocketnet.unixUnixStream, over a path rather than an addressnet.tlsTLS over a TCP stream net.dtlsDTLS over a UDP socket net.ipparsing, formatting and classifying IP addresses net.addrSocketAddrV4 and SocketAddrV6net.pollasking which of a set of sockets is ready
Submodule What it is for
os.pathjoining, resolving and comparing path strings os.fsdirectories, permissions, symlinks, globbing os.envreading, writing and listing environment variables os.processprocess identity, subprocesses, signals os.systemfacts about the process, the runtime and the machine os.tempfilethe temporary directory, and scratch files in it
Submodule What it is for
rpc.messageRequest, Notification, Response, and reading and writing them as JSONrpc.errorRpcError, the codes the specification defines, and the module’s other errorsrpc.serviceService and the Context its handlers are givenrpc.httphttp_handler() and HttpClient, JSON-RPC over HTTPrpc.framingHeaderFraming, LineFraming and MessageFraming, telling messages apartrpc.transportthe transports, WebSockets among them, and pipe() between isolates rpc.endpointEndpoint, a service on a connectionrpc.serverserve(), an endpoint for every connection to a listening socket
Submodule What it is for
sql.driverthe contract an adapter implements, and the capability flags sql.errorsevery error a database raises, under one root sql.paramsrewriting ? and :name into whatever an engine wants sql.typeshow Zuri values and database values correspond sql.decimalDecimal, for a column a float must not holdsql.resultResultSet and ExecResultsql.cursorreading a result a row at a time sql.statementa statement compiled once and run many times sql.transactionTransaction, and the savepoints inside itsql.connectionthe Connection a program holds sql.crudbuilding the four statements that are always the same sql.schemaasking a database what is in it sql.poolkeeping connections open and lending them out sql.sqlitethe SQLite adapter, and its blobs, backups and hooks sql.postgresthe PostgreSQL adapter, and LISTEN/NOTIFY sql.mysqlthe MySQL and MariaDB adapter
Submodule What it is for
mail.errorsevery error the mail stack raises, under one root mail.addressreading and writing the addresses in a header mail.headersthe header block, in order and without regard to case mail.encodingthe encodings a header and a body use mail.contentContent-Type and Content-Dispositionmail.messagea message, its MIME tree, and building one mail.dkimsigning a message and checking a signature mail.saslthe authentication mechanisms all three protocols share mail.streama line-oriented connection, and negotiating TLS over one mail.smtpthe sending and receiving ends of SMTP mail.imapthe client and server ends of IMAP, and where mail is kept mail.imap.parserthe IMAP grammar mail.imap.storeMailStore, MaildirStore and MemoryStoremail.pop3the client end of POP3 mail.poolrunning a mail server on more than one connection at once
Submodule What it is for
test.expectExpect and every matcher on ittest.runnercollecting the declarations and running them test.reporterReporter, and the seven built-in onestest.resultCase, Suite, Failure and Summarytest.mockMock, mock() and spy_on()test.snapshotthe snapshot store and its file format test.conductdiscovering and running a directory of test files test.diffstructural equality, and rendering what differs test.formatrendering any value for a failure message test.sourcereading a stack trace back to the failing line test.styleterminal colour, symbols and width test.errorAssertionError and TestSetupErrortest.contextwhat is true while one test is running
Submodule What it is for
validate.validatorsthe one-line entry points, one per rule validate.validatorValidator, the fluent buildervalidate.schemaSchema, validating a whole dictionary at oncevalidate.ruleRule, the base class custom rules extendvalidate.rulesevery built-in rule
Submodule What it is for
wire.compileturning a parsed template into an instruction tree wire.renderwalking a compiled template and writing the page wire.expressionthe language between {{ and }} wire.filtersthe filters every template starts with wire.escapecontext-aware escaping wire.loaderresolving the path in an x-include wire.normalizerewriting the pseudo elements before parsing wire.valueshow a template reads the values it is given wire.constantsthe directive names Wire reserves wire.errorsthe module’s errors, and the locations they carry
Submodule What it is for
zuri.tokentokenize(), and the Token type it returnszuri.astparse(), and the Node type it returnszuri.compilecompile(), and the Instr type it returnszuri.reflectinspecting a live function, class, module or instance
A file in ./.zuri/libs/ shadows a standard library module of the same
name, because that directory is searched first. See
The Module System .