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  1. The standard library

std/prelude

The package of re-exports that is in scope in every file of a project, unless project.trb names another one.

The generated reference of std/prelude has every public construct with its signature, its doc comment and its examples.

std/prelude declares nothing of its own: every name it re-exports lives in a package that can also be imported directly. The prelude is the rule - why the pure part of the standard library is in scope everywhere and a capability such as std/fs or Clock never is, and how a project replaces this package with another one. What follows here is exactly what std/prelude re-exports today.

Import#

The prelude needs no import: it is what every other file's imports are measured against. A project names a different one by setting prelude in project.trb (see std/project).

const values: List<Int?> = [1, None, 3]
print(values.filterMap { _ }.sum())

Declarations#

What is re-exported#

public use Void, Never, panic, Bool, Option, Result, Error from "std/core"
public use Option.Some, Option.None, Result.Ok, Result.Fail from "std/core"
public use Equals, Compare, Ordering, Hash, combineHashes from "std/core"
public use From, Into, TryFrom, TryInto, Show, LiteralParseError from "std/core"
public use Add, Subtract, Multiply, Divide, Remainder, Negate, OrElse from "std/core"
public use Index, MutableIndex, Slice, MutableSlice from "std/core"
public use Range, RangeFrom, RangeTo, Bounds from "std/core"
public use Array, Buffer, Shared, isSame from "std/core"
public use do, unless, retry, Close from "std/core"
public use Predicate, Action, Transform from "std/core"
public use Char, String from "std/text"
public use Numeric, Signed, Real, Bits, NumberParseError, NumberRangeError from "std/number"
public use Int8, Int16, Int32, Int64 from "std/number"
public use UInt8, UInt16, UInt32, UInt64 from "std/number"
public use Float32, Float64, Decimal from "std/number"
public use Int, UInt, Float from "std/number"
public use ByteSize from "std/number"
public use List, ArrayList, TrieList from "std/collections"
public use Map, TrieMap, HashMap, Set, TrieSet, HashSet from "std/collections"
public use Stack, ArrayStack, Queue, ArrayQueue from "std/collections"
public use Iterator, Iterate, Length from "std/iteration"
public use Stage from "std/iteration"
public use mapping, filtering, filterMapping, mappingWhile, flatMapping from "std/iteration"
public use taking, takingWhile, skipping, indexing, chunking from "std/iteration"
public use Accumulator, Merge, ListAccumulator, collector, mergingCollector, into, listing from "std/iteration"
public use counting, summing, averaging, minBy, maxBy, joining, partitioningBy, groupingBy from "std/iteration"
public use Encode, Decode, Describe, DecodeError, Format, rendered from "std/encoding"
public use Encoder, Decoder, Describer, FieldDescription, FieldDefault, EncodedValue from "std/encoding"
public use Expression, ExpressionNode, TypeReference, SourceLocation, UnaryOperator, BinaryOperator, assert, nameOf from "std/expression"
public use Task, Channel, ChannelClosed, Cancelled, TimedOut, spawn, both from "std/task"
public use Parallel from "std/parallel"
public use Iterate.parallel, Cut.parallel, List.parallel from "std/parallel"
public use Source, Sink, Bytes from "std/stream"
public use print, printError from "std/console"
public use Json, JsonValue, JsonError from "std/json"
public use Duration, Instant, Timestamp from "std/time"
public use Int64.seconds, Int64.milliseconds from "std/time"
public use Path, PathError from "std/path"
public use Uri, UriReference, UriError from "std/uri"

Timestamp is in beside Duration and Instant because it is a value too: a point on the wall clock in a field or a signature reads no clock, and only Clock - an import - does (see std/time). Path is in because it is a value like Duration: it names a file and reads nothing, so a signature can say it without an import, while File and Directory - which touch what a path names - stay behind use ... from "std/fs". Uri, UriReference and UriError are in for the same reason: a URI names a resource and opens nothing, and what reaches it - std/http, std/network - stays an import, as do Urn, UriTemplate and the rest of std/uri. ByteSize is a value like Duration as well: a number of bytes in a field or a limit, and 64.megabytes() writes one with no import, because std/number owns Int64 (see std/number). std/linear stays out: a program that computes with vectors imports it.

Every re-export keeps its original name, so use Option from "std/prelude" and use Option from "std/core" name the same type. There is no math namespace: the power is **, and the constants and functions are Real's members (Float.pi, angle.sine(), value.naturalLogarithm()). Result.Ok, Result.Fail, Option.Some and Option.None are the one reason these two types can be matched and constructed without their type name, in a pattern (None =>) as well as in an expression (Ok value). Predicate, Action and Transform are here so that a signature taking a closure reads the same in every file: predicate: Predicate<Item> rather than predicate: (value: Item) => Bool (see Predicate, Action and Transform). Cancelled, TimedOut and both come with Task because a program that spawns one needs them to say how it ended and to wait for two at once (see std/task). using is not in the list: it is grammar, a binding form, and needs no name in scope.

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