Safe Haskell	None
Language	Haskell2010

Database.PostgreSQL.Tx

Synopsis

data TxM a
unsafeRunIOInTxM :: IO a -> TxM a
class Tx (f :: * -> *) where
- type TxEnv f :: *
- tx :: TxEnv f -> f a -> TxM a
class UnsafeTx (io :: * -> *) (t :: * -> *) | t -> io where
- unsafeIOTx :: io a -> t a
unsafeReaderIOTx :: UnsafeTx (ReaderT r io) (ReaderT r t) => (r -> io a) -> ReaderT r t a

Documentation

Instances

Monad TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods (>>=) :: TxM a -> (a -> TxM b) -> TxM b # (>>) :: TxM a -> TxM b -> TxM b # return :: a -> TxM a # fail :: String -> TxM a #
Functor TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods fmap :: (a -> b) -> TxM a -> TxM b # (<$) :: a -> TxM b -> TxM a #
Applicative TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods pure :: a -> TxM a # (<>) :: TxM (a -> b) -> TxM a -> TxM b # liftA2 :: (a -> b -> c) -> TxM a -> TxM b -> TxM c # (>) :: TxM a -> TxM b -> TxM b # (<*) :: TxM a -> TxM b -> TxM a #
(TypeError (Text "MonadIO is banned in TxM; use 'unsafeRunIOInTxM' if you are sure this is safe IO") :: Constraint) => MonadIO TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods liftIO :: IO a -> TxM a #
UnsafeTx IO TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods unsafeIOTx :: IO a -> TxM a Source #
Tx (ReaderT r TxM) Source #
Instance details Defined in Database.PostgreSQL.Tx Associated Types type TxEnv (ReaderT r TxM) :: Type Source # Methods tx :: TxEnv (ReaderT r TxM) -> ReaderT r TxM a -> TxM a Source #
type TxEnv (ReaderT r TxM) Source #
Instance details Defined in Database.PostgreSQL.Tx type TxEnv (ReaderT r TxM) = r

class Tx (f :: * -> *) where Source #

Type class for converting an f to TxM given a TxEnv.

Associated Types

type TxEnv f :: * Source #

The runtime environment needed to convert f to TxM.

Methods

tx :: TxEnv f -> f a -> TxM a Source #

Converts an f to a TxM.

Instances

Tx (ReaderT r TxM) Source #
Instance details Defined in Database.PostgreSQL.Tx Associated Types type TxEnv (ReaderT r TxM) :: Type Source # Methods tx :: TxEnv (ReaderT r TxM) -> ReaderT r TxM a -> TxM a Source #

class UnsafeTx (io :: * -> *) (t :: * -> *) | t -> io where Source #

Promote an unsafe io action to a safe t transaction (will be some form of TxM).

Methods

Converts an io action to a t, which will be some form of TxM.

Instances

UnsafeTx IO TxM Source #
Instance details Defined in Database.PostgreSQL.Tx Methods unsafeIOTx :: IO a -> TxM a Source #
UnsafeTx io t => UnsafeTx (ReaderT r io) (ReaderT r t) Source #
Instance details Defined in Database.PostgreSQL.Tx Methods unsafeIOTx :: ReaderT r io a -> ReaderT r t a Source #

Promotes an unsafe io function to some ReaderT over TxM.