KV.hs

{-# LANGUAGE RecordWildCards, MultiParamTypeClasses, FlexibleInstances #-}

class KVEntity a b where
    kvIdentity      :: a -> KVIdentifier
    kvProperties    :: a -> Value
    kvLastModified  :: a -> UTCTime
    kvClass         :: a -> KVClass
    kvRelations     :: a -> [KVLink]
    kvCachedRels    :: a -> [b]

    kvProperties _ = emptyObject
    kvCachedRels _ = []
    kvRelations  _ = []

data KVFullEntity a = KVFullEntity
    { kvFullClass           :: KVClass
    , kvFullProperties      :: Value
    , kvFullIdentity        :: KVIdentifier
    , kvFullLastModified    :: UTCTime
    , kvFullRelations       :: [KVLink]
    , kvFullCachedRels      :: [a]
    }
instance (KVEntity a a) => KVEntity (KVFullEntity a) a where
    kvIdentity KVFullEntity{..}     = kvFullIdentity
    kvProperties KVFullEntity{..}   = kvFullProperties
    kvLastModified KVFullEntity{..} = kvFullLastModified
    kvClass KVFullEntity{..}        = kvFullClass
    kvRelations KVFullEntity{..}    = kvFullRelations
    kvCachedRels KVFullEntity{..}   = kvFullCachedRels