Data.Storage

class (Storable a) <= MonadStorage m a  where

Members

• store :: a -> m (Either StorageError Unit)

  Writes a storable a in a monad m, returning Left NoStorageError representing the lack of a storage on error or returning Right Unit on success.

• retrieve :: String -> m (Either StorageError a)

  Reads a storable a when given a key in monad m, returning either a Left containing an error representing unavailable storage, decoding error or no value matching the supplied' key.

Instances

• (Storable a) => MonadStorage LocalStorage a
• (Storable a) => MonadStorage SessionStorage a
• (Storable a, MonadState (Map String String) m) => MonadStorage m a

class Storable a  where

Members

• key :: a -> String

  Produces a key from the given a. This is most appropriately an id or something like it.

• prefix :: Proxy a -> String

  When given a proxy of a returns a prefix that all items with that type will be stored with.

• serialize :: a -> String

  Takes an a and (hopefully) reliably turns it into a string; this should be symmetric with deserialize. This can be conveniently implemented using Simple.JSON.

• deserialize :: String -> Either StorageError a

  Takes a string and either successfully decodes it into a Right a or returns a DecodingError that contains a NonEmptyList ForeignError. This matches the error value that Simple.JSON returns.

data StorageError

Constructors

• NoValueError String
• NoStorageError
• DecodeError (NonEmptyList ForeignError)

Instances

• Generic StorageError _
• Show StorageError
• Eq StorageError

getKey :: forall a. Storable a => a -> String

Given a storable a will produce the key that it would have in storage.

makeKey :: forall a. Storable a => Proxy a -> String -> String

When given a Proxy a and a key will produce the corresponding composite key.