Data.ULID

This library implements the Universally Unique Lexicographically Sortable Identifier, as described at https://github.com/alizain/ulid.

UUID can be suboptimal for many uses-cases because:

• It isn't the most character efficient way of encoding 128 bits of randomness
• UUID v1/v2 is impractical in many environments, as it requires access to a unique, stable MAC address
• UUID v3/v5 requires a unique seed and produces randomly distributed IDs, which can cause fragmentation in many data structures
• UUID v4 provides no other information than randomness which can cause fragmentation in many data structures

Instead, herein is proposed ULID:

• 128-bit compatibility with UUID
• 1.21e+24 unique ULIDs per millisecond
• Lexicographically sortable!
• Canonically encoded as a 26 character string, as opposed to the 36 character UUID
• Uses Crockford's base32 for better efficiency and readability (5 bits per character)
• Case insensitive
• No special characters (URL safe)

Documentation

data ULID

Constructors

ULID

Fields

• timeStamp :: !ULIDTimeStamp
• random :: !ULIDRandom

Instances

Eq ULID

Methods

(==) :: ULID -> ULID -> Bool

(/=) :: ULID -> ULID -> Bool

Data ULID

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ULID -> c ULID

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ULID

toConstr :: ULID -> Constr

dataTypeOf :: ULID -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c ULID)

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ULID)

gmapT :: (forall b. Data b => b -> b) -> ULID -> ULID

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ULID -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ULID -> r

gmapQ :: (forall d. Data d => d -> u) -> ULID -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> ULID -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ULID -> m ULID

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ULID -> m ULID

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ULID -> m ULID

Ord ULID

Methods

compare :: ULID -> ULID -> Ordering

(<) :: ULID -> ULID -> Bool

(<=) :: ULID -> ULID -> Bool

(>) :: ULID -> ULID -> Bool

(>=) :: ULID -> ULID -> Bool

max :: ULID -> ULID -> ULID

min :: ULID -> ULID -> ULID

Read ULID

Methods

readsPrec :: Int -> ReadS ULID

readList :: ReadS [ULID]

readPrec :: ReadPrec ULID

readListPrec :: ReadPrec [ULID]

Show ULID

Methods

showsPrec :: Int -> ULID -> ShowS

show :: ULID -> String

showList :: [ULID] -> ShowS

Binary ULID

Methods

put :: ULID -> Put

get :: Get ULID

putList :: [ULID] -> Put

NFData ULID

Methods

rnf :: ULID -> ()

Hashable ULID

Methods

hashWithSalt :: Int -> ULID -> Int

hash :: ULID -> Int

Random ULID

Methods

randomR :: RandomGen g => (ULID, ULID) -> g -> (ULID, g)

random :: RandomGen g => g -> (ULID, g)

randomRs :: RandomGen g => (ULID, ULID) -> g -> [ULID]

randoms :: RandomGen g => g -> [ULID]

randomRIO :: (ULID, ULID) -> IO ULID

randomIO :: IO ULID

getULIDTime

Arguments

:: POSIXTime

The specified UNIX time (seconds) to millisecond precision, e.g. 1469918176.385

-> IO ULID

Derive a ULID using a specified time and default random number generator

getULID :: IO ULID

Derive a ULID using the current time and default random number generator

ulidToInteger :: ULID -> Integer

Convert a ULID to its corresponding (at most) 128-bit Integer. Integer equivalents retain sortable trait (same sort order). This could be useful for storing in a database using a smaller field than storing the Show'n string, but still human-readable unlike the Binary version.

ulidFromInteger

Arguments

:: Integer

The ULID's Integer equivalent, as generated by toInteger

-> ULID

Convert a ULID from its corresponding 128-bit Integer.