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-rw-r--r--server/src/Model/Query.hs32
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diff --git a/server/src/Model/Query.hs b/server/src/Model/Query.hs
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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