Polysemy.KVStore

Effect

data KVStore k v m a where

Models things like Redis, HTTP GET/POST, etc. Things that are keyed, have a value, and may or may not be there.

Constructors

LookupKV :: k -> KVStore k v m (Maybe v)

UpdateKV :: k -> Maybe v -> KVStore k v m ()

Actions

lookupKV :: forall k v r. Member (KVStore k v) r => k -> Sem r (Maybe v)

lookupOrThrowKV :: Members '[KVStore k v, Error e] r => (k -> e) -> k -> Sem r v

Since: 0.3.1.0

existsKV :: forall k v r. Member (KVStore k v) r => k -> Sem r Bool

Since: 0.3.1.0

writeKV :: Member (KVStore k v) r => k -> v -> Sem r ()

deleteKV :: forall k v r. Member (KVStore k v) r => k -> Sem r ()

updateKV :: forall k v r. Member (KVStore k v) r => k -> Maybe v -> Sem r ()

modifyKV

Arguments

:: Member (KVStore k v) r

=> v

Default value if the key isn't present

-> (v -> v)

-> k

-> Sem r ()

Since: 0.3.1.0

Interpretations

runKVStoreAsState :: Ord k => Sem (KVStore k v ': r) a -> Sem (State (Map k v) ': r) a

runKVStorePurely :: Ord k => Map k v -> Sem (KVStore k v ': r) a -> Sem r (Map k v, a)