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GHC 9.10.3 · lts/ghc-9.10.x · 248f8f0 · 2026-10-05

Modulepolysemy-kvstore-0.1.3.0Haskell2010

Polysemy.KVStore

1 type
11 values

Packagepolysemy-kvstore-0.1.3.0
Exports12
LanguageHaskell2010
LicenceMIT
SourceKVStore.hs

Effect

1 declaration

datadata KVStore k v (m :: Type -> Type) 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

7 declarations

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

valuelookupOrThrowKV

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

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

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

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

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

valuemodifyKV

:: Member (KVStore k v) r
=> v
Default value if the key isn't present
-> (v -> v)
-> k
-> Sem r ()

Interpreters

4 declarations

valuerunKVStoreAsState

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

Run a KVStore as a State effect containing a Map.

valuerunKVStorePure

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

Run a KVStore purely as a Map.

valuerunKVStoreAsKVStore

:: (k -> k')
A function to transform the key into the interpreted key.
-> (v -> v')
A function to transform the value into the interpreted value.
-> (v' -> v)
A function to transform the interpreted key back into the current value.
-> Sem (KVStore k v ': r) a
-> Sem (KVStore k' v' ': r) a

Run a KVStore in terms of another KVStore by way of pure key and value transformations.

valuerunKVStoreAsKVStoreSem

:: Members '[KVStore k' v'] r
=> (k -> Sem r k')
A function to transform the key into the interpreted key.
-> (v -> Sem r v')
A function to transform the value into the interpreted value.
-> (v' -> Sem r v)
A function to transform the interpreted value back into the current value.
-> Sem (KVStore k v ': r) a
-> Sem r a

Run a KVStore in terms of another KVStore by way of transforming the keys and values with Sem functions.