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 text, as opposed to the 36 character UUID
• Uses Douglas Crockford's base32 for better efficiency and readability (5 bits per character)
• Case insensitive
• No special characters (URL safe)

Documentation

data ULID

t <- getULIDTimeStamp
r <- getULIDRandom
pure $ ULID t r

Constructors

ULID

Fields

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

Instances

Eq ULID

Defined in Data.ULID

Methods

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

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

Data ULID

Defined in 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

Defined in Data.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

Defined in Data.ULID

Methods

readsPrec :: Int -> ReadS ULID

readList :: ReadS [ULID]

readPrec :: ReadPrec ULID

readListPrec :: ReadPrec [ULID]

Show ULID

Defined in Data.ULID

Methods

showsPrec :: Int -> ULID -> ShowS

show :: ULID -> String

showList :: [ULID] -> ShowS

Binary ULID

Defined in Data.ULID

Methods

put :: ULID -> Put

get :: Get ULID

putList :: [ULID] -> Put

NFData ULID

Because of the strictness annotations, this shouldn't be needed and shouldn't do anything. This is tested and confirmed in the benchmark, but since the work to put it here has already been done it's no harm to leave it in.

Defined in Data.ULID

Methods

rnf :: ULID -> ()

Hashable ULID

Defined in Data.ULID

Methods

hashWithSalt :: Int -> ULID -> Int

hash :: ULID -> Int

Random ULID

Defined in Data.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

Specified UNIX time with 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 shown Text, but still human-readable unlike the Binary version.

ulidFromInteger

Arguments

:: Integer

The ULID's Integer equivalent, as generated by toInteger

-> Either Text ULID

Convert a ULID from its corresponding 128-bit Integer.