GGHandler, PersistBackend, and MonadPlus
Hi, Could GGHandler be made an instance of MonadPlus, and PersistBackend have MonadPlus in its context? I have found both to be useful. Jeremy diff from yesod-core-0.8.2/Yesod/Handler.hs 123c123 < import Control.Monad (liftM, join, MonadPlus) ---
import Control.Monad (liftM, join) 249c249 < deriving (Functor, Applicative, Monad, MonadPlus, MonadIO, MonadControlIO)
deriving (Functor, Applicative, Monad, MonadIO, MonadControlIO)
diff from persistent-0.5.1/Database/Persist/Base.hs 54a55,56
import Control.Monad
303c305 < class Monad m => PersistBackend m where ---
class MonadPlus m => PersistBackend m where
diff from persistent-0.5.1/Database/Persist/GenericSql.hs 34c34 < import Control.Monad (liftM, unless) ---
import Control.Monad (liftM, unless, MonadPlus) 63c63 < instance MonadControlIO m => PersistBackend (SqlPersist m) where
instance (MonadPlus m, MonadControlIO m) => PersistBackend (SqlPersist m) where
diff from persistent-0.5.1/Database/Persist/GenericSql/Raw.hs 22a23
import Control.Monad 25c26 < deriving (Monad, MonadIO, MonadTrans, Functor, Applicative, MonadControlIO)
deriving (Monad, MonadIO, MonadTrans, Functor, Applicative, MonadControlIO, MonadPlus)
diff from persistent-mongoDB-0.2.2/Database/Persist/MongoDB.hs 28a29
import Control.Monad (MonadPlus) 37c38 < deriving (Monad, Trans.MonadIO, Functor, Applicative)
deriving (Monad, Trans.MonadIO, Functor, Applicative, MonadPlus)
121c122 < instance (DB.DbAccess m, DB.Service t) => PersistBackend (MongoDBReader t m) where ---
instance (DB.DbAccess m, DB.Service t, MonadPlus m) => PersistBackend (MongoDBReader t m) where
Hi Jeremy,
Hi Jeremy,
Sounds good in general. I've pushed a patch to each of the yesod-core
and persistent repos. The one thing I'm not sure about is adding
MonadPlus to the superclass requirements. Is there a specific reason
that's necessary?
Michael
On Wed, Jun 8, 2011 at 11:16 PM, Jeremy Hughes
Hi,
Could GGHandler be made an instance of MonadPlus, and PersistBackend have MonadPlus in its context? I have found both to be useful.
Jeremy
diff from yesod-core-0.8.2/Yesod/Handler.hs 123c123 < import Control.Monad (liftM, join, MonadPlus) ---
import Control.Monad (liftM, join) 249c249 < deriving (Functor, Applicative, Monad, MonadPlus, MonadIO, MonadControlIO)
deriving (Functor, Applicative, Monad, MonadIO, MonadControlIO)
diff from persistent-0.5.1/Database/Persist/Base.hs 54a55,56
import Control.Monad
303c305 < class Monad m => PersistBackend m where ---
class MonadPlus m => PersistBackend m where
diff from persistent-0.5.1/Database/Persist/GenericSql.hs 34c34 < import Control.Monad (liftM, unless) ---
import Control.Monad (liftM, unless, MonadPlus) 63c63 < instance MonadControlIO m => PersistBackend (SqlPersist m) where
instance (MonadPlus m, MonadControlIO m) => PersistBackend (SqlPersist m) where
diff from persistent-0.5.1/Database/Persist/GenericSql/Raw.hs 22a23
import Control.Monad 25c26 < deriving (Monad, MonadIO, MonadTrans, Functor, Applicative, MonadControlIO)
deriving (Monad, MonadIO, MonadTrans, Functor, Applicative, MonadControlIO, MonadPlus)
diff from persistent-mongoDB-0.2.2/Database/Persist/MongoDB.hs 28a29
import Control.Monad (MonadPlus) 37c38 < deriving (Monad, Trans.MonadIO, Functor, Applicative)
deriving (Monad, Trans.MonadIO, Functor, Applicative, MonadPlus) 121c122 < instance (DB.DbAccess m, DB.Service t) => PersistBackend (MongoDBReader t m) where
instance (DB.DbAccess m, DB.Service t, MonadPlus m) => PersistBackend (MongoDBReader t m) where
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participants (2)
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Jeremy Hughes -
Michael Snoyman