Data.Parameterized.Nonce

This module provides a simple generator of new indexes in the ST monad. It is predictable and not intended for cryptographic purposes.

This module also provides a global nonce generator that will generate 2^64 nonces before looping.

NOTE: The TestEquality and OrdF instances for the Nonce type simply compare the generated nonce values and then assert to the compiler (via unsafeCoerce) that the types ascribed to the nonces are equal if their values are equal.

NonceGenerator

data NonceGenerator (m :: * -> *) (s :: *)

Provides a monadic action for getting fresh typed names.

The first type parameter m is the monad used for generating names, and the second parameter s is used for the counter.

freshNonce :: NonceGenerator m s -> forall k (tp :: k). m (Nonce s tp)

data Nonce (s :: *) (tp :: k)

An index generated by the counter.

Instances

TestEquality k (Nonce k s)

Methods

testEquality :: f a -> f b -> Maybe ((Nonce k s :~: a) b)

HashableF k (Nonce k s)

Methods

hashWithSaltF :: Int -> f tp -> Int

hashF :: f tp -> Int

ShowF k (Nonce k s)

Methods

withShow :: p f -> q tp -> (Show (f tp) -> a) -> a

showF :: f tp -> String

showsF :: f tp -> String -> String

OrdF k (Nonce k s)

Methods

compareF :: ktp x -> ktp y -> OrderingF (Nonce k s) x y

leqF :: ktp x -> ktp y -> Bool

ltF :: ktp x -> ktp y -> Bool

geqF :: ktp x -> ktp y -> Bool

gtF :: ktp x -> ktp y -> Bool

Eq (Nonce k s tp)

Methods

(==) :: Nonce k s tp -> Nonce k s tp -> Bool

(/=) :: Nonce k s tp -> Nonce k s tp -> Bool

Ord (Nonce k s tp)

Methods

compare :: Nonce k s tp -> Nonce k s tp -> Ordering

(<) :: Nonce k s tp -> Nonce k s tp -> Bool

(<=) :: Nonce k s tp -> Nonce k s tp -> Bool

(>) :: Nonce k s tp -> Nonce k s tp -> Bool

(>=) :: Nonce k s tp -> Nonce k s tp -> Bool

max :: Nonce k s tp -> Nonce k s tp -> Nonce k s tp

min :: Nonce k s tp -> Nonce k s tp -> Nonce k s tp

Show (Nonce k s tp)

Methods

showsPrec :: Int -> Nonce k s tp -> ShowS

show :: Nonce k s tp -> String

showList :: [Nonce k s tp] -> ShowS

Hashable (Nonce k s tp)

Methods

hashWithSalt :: Int -> Nonce k s tp -> Int

hash :: Nonce k s tp -> Int

indexValue :: Nonce s tp -> Word64

Accessing a nonce generator

newSTNonceGenerator :: ST t (Some (NonceGenerator (ST t)))

Create a new nonce generator in the ST monad.

newIONonceGenerator :: IO (Some (NonceGenerator IO))

Create a new nonce generator in the ST monad.

withIONonceGenerator :: (forall s. NonceGenerator IO s -> IO r) -> IO r

Create a new nonce generator in the IO monad.

withSTNonceGenerator :: (forall s. NonceGenerator (ST t) s -> ST t r) -> ST t r

Run a ST computation with a new nonce generator in the ST monad.

withGlobalSTNonceGenerator :: (forall t. NonceGenerator (ST t) t -> ST t r) -> r

Create a new counter.

data GlobalNonceGenerator

globalNonceGenerator :: NonceGenerator IO GlobalNonceGenerator

A nonce generator that uses a globally-defined counter.