Data.UUID

This library is useful for comparing, parsing and printing Universally Unique Identifiers. See http://en.wikipedia.org/wiki/UUID for the general idea. See http://tools.ietf.org/html/rfc4122 for the specification.

• Random UUIDs may be generated using nextRandom or your favorite instance of Random.
• We have an implementation of generating a UUID from the hardware MAC address and current system time in Data.UUID.V1.
• For name-based generation of UUIDs using SHA-1 hashing see Data.UUID.V5.

Documentation

data UUID

The UUID type. A Random instance is provided which produces version 4 UUIDs as specified in RFC 4122. The Storable and Binary instances are compatible with RFC 4122, storing the fields in network order as 16 bytes.

Instances

Eq UUID

Data UUID

Ord UUID

Read UUID

Show UUID

Typeable UUID

Storable UUID

Binary UUID

Random UUID

toString :: UUID -> String

Convert a UUID into a hypenated string using lower-case letters. Example:

  toString $ fromString "550e8400-e29b-41d4-a716-446655440000"

fromString :: String -> Maybe UUID

If the passed in String can be parsed as a UUID, it will be. The hyphens may not be omitted. Example:

  fromString "c2cc10e1-57d6-4b6f-9899-38d972112d8c"

Hex digits may be upper or lower-case.

toByteString :: UUID -> ByteString

Encode a UUID into a ByteString in network order.

fromByteString :: ByteString -> Maybe UUID

Extract a UUID from a ByteString in network byte order. The argument must be 16 bytes long, otherwise Nothing is returned.

toWords :: UUID -> (Word32, Word32, Word32, Word32)

Covert a UUID into a sequence of Word32 values. Usefull for when you need to serialize a UUID and neither Storable nor Binary are appropriate. Introduced in version 1.2.2.

fromWords :: Word32 -> Word32 -> Word32 -> Word32 -> UUID

Create a UUID from a sequence of Word32. The opposite of toWords. Useful when you need a total function for constructing UUID values. Introduced in version 1.2.2.

null :: UUID -> Bool

Returns true if the passed-in UUID is the nil UUID.

nil :: UUID

The nil UUID, as defined in RFC 4122. It is a UUID of all zeros. null u iff u == nil.