vault-0.3.0.6: a persistent store for values of arbitrary types

Safe HaskellNone
LanguageHaskell98

Data.Vault.ST.Strict

Contents

Description

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

The Vault type in this module is strict in both keys and values.

Synopsis

Vault

data Vault s

Instances

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.