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author | Joris | 2020-01-30 11:35:31 +0000 |
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committer | Joris | 2020-01-30 11:35:31 +0000 |
commit | 960fa7cb7ae4c57d01306f78cd349f3a8337d0ab (patch) | |
tree | 5077cc720525fb025e4dba65a9a8b631862cbcc8 /server/src/Model/Query.hs | |
parent | 14bdbc8c937f5d0b35c61350dba28cb41c3737cd (diff) | |
parent | 6a04e640955051616c3ad0874605830c448f2d75 (diff) | |
download | budget-960fa7cb7ae4c57d01306f78cd349f3a8337d0ab.tar.gz budget-960fa7cb7ae4c57d01306f78cd349f3a8337d0ab.tar.bz2 budget-960fa7cb7ae4c57d01306f78cd349f3a8337d0ab.zip |
Merge branch 'with-ghcjs' into 'master'
Use Haskell on the frontend
See merge request guyonvarch/shared-cost!2
Diffstat (limited to 'server/src/Model/Query.hs')
-rw-r--r-- | server/src/Model/Query.hs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/server/src/Model/Query.hs b/server/src/Model/Query.hs new file mode 100644 index 0000000..22ae95b --- /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 |