The uuid module

UUIDs (RFC 9562): 128-bit identifiers, written as 0190163d-8694-739b-aea5-966c26f8ad91.

Bring it in with import uuid (or import [Uuid] from uuid). Uuid.v4() makes a random one; Uuid.v7() puts the time first, so ids made later sort later, which keeps database indexes compact. Both draw their random bits from the operating system’s secure source (random.bytes).

Example

import uuid;

main(): int {
    var id = uuid.Uuid.v4();
    var text = id.to_string();                       # such as 9b2c3c1e-...
    assert(uuid.Uuid.parse(text).value() == id, "round trip");
    assert(id.version() == 4, "random");
    return 0;
}

Source: runtime/uuid/module.pep

Uuid

[Value] struct Uuid

A UUID, as a value struct of two 64-bit halves: == compares them and hash hashes them, so a Uuid works as a map key.

Example

var id = Uuid.parse("0190163D-8694-739B-AEA5-966C26F8AD91").value();
assert(id.version() == 7, "the version digit");
assert(id.to_string() == "0190163d-8694-739b-aea5-966c26f8ad91", "lowercase");

Fields

high

var high: ulong

The first 8 bytes, the first byte in the top bits.

low

var low: ulong

The last 8 bytes, the first of them in the top bits.

Constructor

Uuid()

construct(high: ulong, low: ulong)

Makes the UUID with these halves; Uuid(0, 0) is the nil UUID.

Parameters

• high — the first 8 bytes, the first byte in the top bits
• low — the last 8 bytes, the first of them in the top bits

Static methods

v4

static v4(): Uuid

Returns a new random UUID (version 4): 122 random bits.

Returns

• the UUID

Panics

• if the operating system cannot give random bytes, which only a broken system does

v7

static v7(): Uuid

Returns a new time-ordered UUID (version 7): the wall clock’s Unix time in milliseconds in the first 48 bits, then 74 random bits. Ids made in different milliseconds sort by time, both as values and as text; ids made in the same millisecond are in no particular order.

Returns

• the UUID

Panics

• if the operating system cannot give random bytes, which only a broken system does

parse

static parse(text: String): Result<Uuid>

Returns the UUID that text writes: 32 hexadecimal digits, either case, in groups of 8, 4, 4, 4 and 12 separated by -.

Parameters

• text — the UUID as text, such as 0190163d-8694-739b-aea5-966c26f8ad91

Returns

• the UUID, or an error when text is not in that form

Methods

version

version(): int

Returns the version: 4 for v4, 7 for v7, 0 for the nil UUID.

Returns

• the version digit, from 0 to 15

bytes

bytes(): u8[]

Returns the UUID’s 16 bytes, high first, as databases and binary formats store it.

Returns

• 16 bytes

to_string

to_string(): String

Returns the UUID as 32 lowercase hexadecimal digits in groups of 8, 4, 4, 4 and 12, such as 0190163d-8694-739b-aea5-966c26f8ad91.

Returns

• the UUID as text, 36 characters