From 27e11b20b06f2f2dbfb56c0998a63169b4b8abc4 Mon Sep 17 00:00:00 2001
From: Joris
Date: Wed, 8 Nov 2017 23:47:26 +0100
Subject: Use a better project structure

---
 server/src/Model/Query.hs | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 server/src/Model/Query.hs

(limited to 'server/src/Model/Query.hs')

diff --git a/server/src/Model/Query.hs b/server/src/Model/Query.hs
new file mode 100644
index 0000000..d15fb5f
--- /dev/null
+++ b/server/src/Model/Query.hs
@@ -0,0 +1,32 @@
+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
-- 
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