UUID

UUID module: RFC 4122 UUID generation and manipulation.

The UUID type wraps a canonical string representation: "xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx" where M is the version digit and N is the variant digit (8, 9, a, or b).

Supported versions: v4 — randomly generated (RFC 4122 §4.4) v5 — name-based using SHA-1 (RFC 4122 §4.3) NOTE: v5 uses the first 16 bytes of a SHA-1 hash with version/ variant bits set; the resulting UUID is RFC-compliant.

The nil UUID ("00000000-0000-0000-0000-000000000000") is the all-zeros UUID. version/1 returns 0 for the nil UUID.

Types

typeUUIDUUID = UUID(String)#

Functions

fnv4v4()#

Generate a random UUID v4.

UUID.v4() -- e.g. UUID("f47ac10b-58cc-4372-a567-0e02b2c3d479")

Uses the runtime's CSPRNG. Version bits (4) and variant bits (RFC 4122) are set correctly.

fnparseparse(s)#

Parse a UUID string, returning Ok(UUID) or Err(:invalid).

Accepts both upper and lower case hex digits; validates the xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx format (36 characters, 4 dashes).

UUID.parse("f47ac10b-58cc-4372-a567-0e02b2c3d479") -- Ok(UUID(...)) UUID.parse("not-a-uuid") -- Err(:invalid)

fnto_stringto_string(uuid)#

Convert a UUID to its canonical lowercase string representation.

UUID.to_string(UUID.nil()) -- "00000000-0000-0000-0000-000000000000"

fnnilnil()#

The nil UUID: all 128 bits are zero.

UUID.to_string(UUID.nil()) -- "00000000-0000-0000-0000-000000000000"

fnv5v5(namespace, name)#

Generate a name-based UUID v5 (SHA-1, RFC 4122 §4.3).

let dns = UUID.parse("6ba7b810-9dad-11d1-80b4-00c04fd430c8") UUID.v5(dns, "www.example.com") -- deterministic UUID

The namespace must be a valid UUID. The name is an arbitrary string. The result is deterministic: the same namespace + name always produce the same UUID.

fnversionversion(uuid)#

Return the version number of a UUID (1–5), or 0 for unrecognised/nil.

UUID.version(UUID.v4()) -- 4 UUID.version(UUID.nil()) -- 0

fnis_validis_valid(s)#

Return true if the string is a valid UUID in xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx form.

UUID.is_valid("f47ac10b-58cc-4372-a567-0e02b2c3d479") -- true UUID.is_valid("00000000-0000-0000-0000-000000000000") -- true UUID.is_valid("not-a-uuid") -- false