Data.Vault.ST.Lazy

A persistent store for values of arbitrary types. Variant for the ST monad.

The Vault type in this module is strict in the keys but lazy in the values.

Vault

data Vault s

Instances

Monoid (Vault s)

data Key s a

empty :: Vault s

The empty vault.

newKey :: ST s (Key s a)

Create a new key for use with a vault.

lookup :: Key s a -> Vault s -> Maybe a

Lookup the value of a key in the vault.

insert :: Key s a -> a -> Vault s -> Vault s

Insert a value for a given key. Overwrites any previous value.

adjust :: (a -> a) -> Key s a -> Vault s -> Vault s

Adjust the value for a given key if it's present in the vault.

delete :: Key s a -> Vault s -> Vault s

Delete a key from the vault.

union :: Vault s -> Vault s -> Vault s

Merge two vaults (left-biased).

Locker

data Locker s

lock :: Key s a -> a -> Locker s

Put a single value into a Locker.

unlock :: Key s a -> Locker s -> Maybe a

Retrieve the value from the Locker.