`std/identifier`

Identifiers: the trait Identifier and its two types, Uuid (RFC 9562, versions 4 and 7) and Ulid, one IdentifierError for a text that is neither, and the urn:uuid: bridge to std/uri (docs/design/URI.md section 12).

The package is pure: randomness is a Random of std/random and the clock a Timestamp, both arguments, so it has no capability and a test needs no mock. It is not in the prelude; a program that makes identifiers names it.

use Uuid from "std/identifier"
use Random from "std/random"

var source = Random.seeded 42
const identifier = Uuid.version7(source, at: Timestamp.fromUnixNanoseconds 1_790_000_000_000_000_000)
print identifier

Modules

std/identifier/errorIdentifierError: what a text is refused with when it is read as an identifier (docs/design/URI.md section 12).
std/identifier/identifier[Identifier]: what Uuid and Ulid have in common (docs/design/URI.md section 12).
std/identifier/ulid[Ulid]: a ULID, 128 bits of a millisecond and an 80-bit random part, shown as twenty-six characters of Crockford base 32 (docs/design/URI.md section 12).
std/identifier/uuid[Uuid]: a UUID after RFC 9562, versions 4 and 7, and the urn:uuid: bridge to std/uri (docs/design/URI.md section 12).

Everything

trait IdentifierWhat every identifier can do: it is 128 bits, shown as text, read back from it, compared bytewise and usable as the key of a Map or an element of a Set.
type IdentifierErrorWhat a text that is not an identifier is refused with.
extend String with From<Ulid>The twenty-six characters of a ULID.
extend String with From<Uuid>The canonical text of a UUID.
type UlidA ULID: sixteen bytes, the first six of them the milliseconds since 1970 and the last ten random, shown as twenty-six upper-case characters of Crockford base 32.
extend Ulid with TryFrom<String, IdentifierError>Twenty-six characters of Crockford base 32, upper or lower case: the alphabet is the digits and the letters but I, L, O and U, and none of Crockford's aliases for 1 and 0 is read.
extend Uri with From<Uuid>urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6, the URN namespace of RFC 9562 section 4: the bridge of [Uuid] to std/uri, which has no dependency on this package.
type UuidA UUID per RFC 9562: sixteen bytes, shown as the canonical thirty-six lower-case characters (f81d4fae-7dec-11d0-a765-00a0c91e6bf6).
extend Uuid with TryFrom<String, IdentifierError>The thirty-six characters of a UUID of either case: eight, four, four, four and twelve hexadecimal digits separated by dashes.
extend Uuid with TryFrom<Urn, IdentifierError>A urn:uuid: URN read as a UUID.