Data.StableTree.Types.Key

Tools for working with StableTree keys. Just about anything can be a key, so long as there's a sane way to implement IsKey and the standard Ord class.

Typical users don't need to worry about anything here other than perhaps IsKey.

Documentation

class IsKey k where

Type class for anything that we can use as a key. The goal here is to wrap up a function that can generate a high-entropy eight-bit hash. Speed is somewhat important here, but since we only actually look at four bits of the hash, it really shouldn't be a problem to quickly generate sufficiently random data.

Implementors probably want to use hashSerialize, hashBinary, or hashByteString when writing their hash functions.

Methods

hash :: k -> Word8

Generate an 8-bit hash

Instances

IsKey Char

IsKey Double

IsKey Float

IsKey Int

IsKey Int8

IsKey Int16

IsKey Int32

IsKey Int64

IsKey Integer

IsKey Word

IsKey Word8

IsKey Word16

IsKey Word32

IsKey Word64

IsKey ByteString

IsKey ByteString

data Key t k

A wrapper for keys; this has an ephemeral t that will be either Terminal or Nonterminal depending on the result of hash k.

Instances

Eq k => Eq (Key t k)

Ord k => Ord (Key t k)

Show k => Show (Key t k)

data SomeKey k

A sum type to contain either a Terminal or a Nonterminal Key

Constructors

SomeKey_T (Key Terminal k)

SomeKey_N (Key Nonterminal k)

Instances

Eq k => Eq (SomeKey k)

Ord k => Ord (SomeKey k)

Show k => Show (SomeKey k)

data Terminal

Used to indicate that a Key is terminal

data Nonterminal

Used to indicate that a Key is not terminal

wrap :: IsKey k => k -> SomeKey k

Do the magic of wrapping up a key into a SomeKey

unwrap :: SomeKey k -> k

Extract the original key from a wrapped one

hashSerialize :: Serialize t => t -> Word8

Calculate a hash for an instance of Serialize

hashBinary :: Binary t => t -> Word8

Calculate a hash for an instance of Binary

hashByteString :: ByteString -> Word8

Calculate a hash for a ByteString