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|
module Model.Query
( Query(..)
, run
) where
import Data.Functor (Functor)
import Database.SQLite.Simple (Connection)
import qualified Database.SQLite.Simple as SQLite
data Query a = Query (Connection -> IO a)
instance Functor Query where
fmap f (Query call) = Query (fmap f . call)
instance Applicative Query where
pure x = Query (const $ return x)
(Query callF) <*> (Query callX) = Query (\conn -> do
x <- callX conn
f <- callF conn
return (f x))
instance Monad Query where
(Query callX) >>= f = Query (\conn -> do
x <- callX conn
case f x of Query callY -> callY conn)
run :: Query a -> IO a
run (Query call) = do
conn <- SQLite.open "database"
result <- call conn
_ <- SQLite.close conn
return result
|
