UUID

Generate and parse Universally Unique Identifiers (UUIDs). Supports UUID versions 4 (random) and 7 (timestamp-based).

import Encoding.UUID

Generation

UUID.v4

() -> String

Generate a random UUID version 4. Uses cryptographically secure random bytes.

id = UUID.v4()
# "550e8400-e29b-41d4-a716-446655440000"

UUID.v7

() -> String

Generate a timestamp-based UUID version 7. Includes millisecond timestamp for time-ordered sorting. Ideal for database primary keys.

id = UUID.v7()
# "01932c19-8e80-7def-8c8a-5b6d43a2c1e0"

# UUIDs generated later sort after earlier ones
id1 = UUID.v7()
id2 = UUID.v7()
# id1 < id2 (lexicographically)

UUID.nil

() -> String

Get the nil UUID (all zeros). Useful as a placeholder or null value.

null-id = UUID.nil()
# "00000000-0000-0000-0000-000000000000"

Validation

UUID.valid?

String -> Bool

Check if a string is a valid UUID format. Accepts both with and without hyphens, case insensitive.

UUID.valid? "550e8400-e29b-41d4-a716-446655440000"  # true
UUID.valid? "550E8400E29B41D4A716446655440000"      # true
UUID.valid? "not-a-uuid"                          # false

Parsing

UUID.parse

String -> Option a

Parse a UUID and extract its components: version, variant, and timestamp (for v7). Returns None for invalid UUIDs.

match UUID.parse "01932c19-8e80-7def-8c8a-5b6d43a2c1e0"
  | Some info ->
    println "Version: ${info.version}"  # 7
    println "Variant: ${info.variant}"  # "RFC 4122"
  | None -> println "Invalid UUID"

UUID v4 vs v7

Property	v4 (Random)	v7 (Timestamp)
Uniqueness	Random 122 bits	Timestamp + random
Sortable	No	Yes (chronological)
DB Indexing	Poor (random)	Excellent (sequential)
Use Case	Session IDs, tokens	Primary keys, event IDs