ghc-lib-parser-9.8.2.20240223: The GHC API, decoupled from GHC versions
Safe HaskellNone
LanguageHaskell2010

GHC.Data.Maybe

Contents

Synopsis

Documentation

listToMaybe :: [a] -> Maybe a #

data Maybe a #

Constructors

Nothing 
Just a 

Instances

Instances details
MonadFail Maybe 
Instance details

Defined in Control.Monad.Fail

Methods

fail :: String -> Maybe a #

MonadFix Maybe 
Instance details

Defined in Control.Monad.Fix

Methods

mfix :: (a -> Maybe a) -> Maybe a #

MonadZip Maybe 
Instance details

Defined in Control.Monad.Zip

Methods

mzip :: Maybe a -> Maybe b -> Maybe (a, b)

mzipWith :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c

munzip :: Maybe (a, b) -> (Maybe a, Maybe b)

Foldable Maybe 
Instance details

Defined in Data.Foldable

Methods

fold :: Monoid m => Maybe m -> m

foldMap :: Monoid m => (a -> m) -> Maybe a -> m #

foldMap' :: Monoid m => (a -> m) -> Maybe a -> m

foldr :: (a -> b -> b) -> b -> Maybe a -> b #

foldr' :: (a -> b -> b) -> b -> Maybe a -> b

foldl :: (b -> a -> b) -> b -> Maybe a -> b #

foldl' :: (b -> a -> b) -> b -> Maybe a -> b #

foldr1 :: (a -> a -> a) -> Maybe a -> a #

foldl1 :: (a -> a -> a) -> Maybe a -> a #

toList :: Maybe a -> [a]

null :: Maybe a -> Bool #

length :: Maybe a -> Int #

elem :: Eq a => a -> Maybe a -> Bool #

maximum :: Ord a => Maybe a -> a #

minimum :: Ord a => Maybe a -> a #

sum :: Num a => Maybe a -> a #

product :: Num a => Maybe a -> a #

Eq1 Maybe 
Instance details

Defined in Data.Functor.Classes

Methods

liftEq :: (a -> b -> Bool) -> Maybe a -> Maybe b -> Bool

Ord1 Maybe 
Instance details

Defined in Data.Functor.Classes

Methods

liftCompare :: (a -> b -> Ordering) -> Maybe a -> Maybe b -> Ordering

Read1 Maybe 
Instance details

Defined in Data.Functor.Classes

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Maybe a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Maybe a]

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Maybe a)

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Maybe a]

Show1 Maybe 
Instance details

Defined in Data.Functor.Classes

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Maybe a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Maybe a] -> ShowS

Traversable Maybe 
Instance details

Defined in Data.Traversable

Methods

traverse :: Applicative f => (a -> f b) -> Maybe a -> f (Maybe b) #

sequenceA :: Applicative f => Maybe (f a) -> f (Maybe a) #

mapM :: Monad m => (a -> m b) -> Maybe a -> m (Maybe b) #

sequence :: Monad m => Maybe (m a) -> m (Maybe a) #

Alternative Maybe 
Instance details

Defined in GHC.Base

Methods

empty :: Maybe a

(<|>) :: Maybe a -> Maybe a -> Maybe a

some :: Maybe a -> Maybe [a]

many :: Maybe a -> Maybe [a]

Applicative Maybe 
Instance details

Defined in GHC.Base

Methods

pure :: a -> Maybe a #

(<*>) :: Maybe (a -> b) -> Maybe a -> Maybe b #

liftA2 :: (a -> b -> c) -> Maybe a -> Maybe b -> Maybe c #

(*>) :: Maybe a -> Maybe b -> Maybe b #

(<*) :: Maybe a -> Maybe b -> Maybe a #

Functor Maybe 
Instance details

Defined in GHC.Base

Methods

fmap :: (a -> b) -> Maybe a -> Maybe b #

(<$) :: a -> Maybe b -> Maybe a #

Monad Maybe 
Instance details

Defined in GHC.Base

Methods

(>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b #

(>>) :: Maybe a -> Maybe b -> Maybe b #

return :: a -> Maybe a #

MonadPlus Maybe 
Instance details

Defined in GHC.Base

Methods

mzero :: Maybe a

mplus :: Maybe a -> Maybe a -> Maybe a

NFData1 Maybe 
Instance details

Defined in Control.DeepSeq

Methods

liftRnf :: (a -> ()) -> Maybe a -> ()

MonadThrow Maybe 
Instance details

Defined in Control.Monad.Catch

Methods

throwM :: (HasCallStack, Exception e) => e -> Maybe a

Generic1 Maybe 
Instance details

Defined in GHC.Generics

Associated Types

type Rep1 Maybe 
Instance details

Defined in GHC.Generics

type Rep1 Maybe = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))

Methods

from1 :: Maybe a -> Rep1 Maybe a

to1 :: Rep1 Maybe a -> Maybe a

OutputableP env a => OutputableP env (Maybe a) Source # 
Instance details

Defined in GHC.Utils.Outputable

Methods

pdoc :: env -> Maybe a -> SDoc Source #

Lift a => Lift (Maybe a :: Type) Source # 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Quote m => Maybe a -> m Exp Source #

liftTyped :: forall (m :: Type -> Type). Quote m => Maybe a -> Code m (Maybe a) Source #

Lift a => Lift (Maybe a :: Type) 
Instance details

Defined in Language.Haskell.TH.Syntax

Methods

lift :: Quote m => Maybe a -> m Exp

liftTyped :: forall (m :: Type -> Type). Quote m => Maybe a -> Code m (Maybe a)

Data a => Data (Maybe a) 
Instance details

Defined in Data.Data

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Maybe a -> c (Maybe a)

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Maybe a)

toConstr :: Maybe a -> Constr

dataTypeOf :: Maybe a -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Maybe a))

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Maybe a))

gmapT :: (forall b. Data b => b -> b) -> Maybe a -> Maybe a

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Maybe a -> r

gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Maybe a -> r

gmapQ :: (forall d. Data d => d -> u) -> Maybe a -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Maybe a -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a)

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a)

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Maybe a -> m (Maybe a)

Semigroup a => Monoid (Maybe a) 
Instance details

Defined in GHC.Base

Methods

mempty :: Maybe a #

mappend :: Maybe a -> Maybe a -> Maybe a #

mconcat :: [Maybe a] -> Maybe a #

Semigroup a => Semigroup (Maybe a) 
Instance details

Defined in GHC.Base

Methods

(<>) :: Maybe a -> Maybe a -> Maybe a

sconcat :: NonEmpty (Maybe a) -> Maybe a

stimes :: Integral b => b -> Maybe a -> Maybe a

Generic (Maybe a) 
Instance details

Defined in GHC.Generics

Associated Types

type Rep (Maybe a) 
Instance details

Defined in GHC.Generics

type Rep (Maybe a) = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))

Methods

from :: Maybe a -> Rep (Maybe a) x

to :: Rep (Maybe a) x -> Maybe a

SingKind a => SingKind (Maybe a) 
Instance details

Defined in GHC.Generics

Associated Types

type DemoteRep (Maybe a) 
Instance details

Defined in GHC.Generics

type DemoteRep (Maybe a) = Maybe (DemoteRep a)

Methods

fromSing :: forall (a0 :: Maybe a). Sing a0 -> DemoteRep (Maybe a)

Read a => Read (Maybe a) 
Instance details

Defined in GHC.Read

Methods

readsPrec :: Int -> ReadS (Maybe a) #

readList :: ReadS [Maybe a] #

readPrec :: ReadPrec (Maybe a)

readListPrec :: ReadPrec [Maybe a]

Show a => Show (Maybe a) 
Instance details

Defined in GHC.Show

Methods

showsPrec :: Int -> Maybe a -> ShowS #

show :: Maybe a -> String #

showList :: [Maybe a] -> ShowS #

Binary a => Binary (Maybe a) 
Instance details

Defined in Data.Binary.Class

Methods

put :: Maybe a -> Put

get :: Get (Maybe a)

putList :: [Maybe a] -> Put

NFData a => NFData (Maybe a) 
Instance details

Defined in Control.DeepSeq

Methods

rnf :: Maybe a -> ()

Binary a => Binary (Maybe a) Source # 
Instance details

Defined in GHC.Utils.Binary

Methods

put_ :: BinHandle -> Maybe a -> IO () Source #

put :: BinHandle -> Maybe a -> IO (Bin (Maybe a)) Source #

get :: BinHandle -> IO (Maybe a) Source #

Outputable a => Outputable (Maybe a) Source # 
Instance details

Defined in GHC.Utils.Outputable

Methods

ppr :: Maybe a -> SDoc Source #

Eq (DeBruijn a) => Eq (DeBruijn (Maybe a)) Source # 
Instance details

Defined in GHC.Core.Map.Type

Methods

(==) :: DeBruijn (Maybe a) -> DeBruijn (Maybe a) -> Bool #

(/=) :: DeBruijn (Maybe a) -> DeBruijn (Maybe a) -> Bool #

Eq a => Eq (Maybe a) 
Instance details

Defined in GHC.Maybe

Methods

(==) :: Maybe a -> Maybe a -> Bool #

(/=) :: Maybe a -> Maybe a -> Bool #

Ord a => Ord (Maybe a) 
Instance details

Defined in GHC.Maybe

Methods

compare :: Maybe a -> Maybe a -> Ordering #

(<) :: Maybe a -> Maybe a -> Bool #

(<=) :: Maybe a -> Maybe a -> Bool #

(>) :: Maybe a -> Maybe a -> Bool #

(>=) :: Maybe a -> Maybe a -> Bool #

max :: Maybe a -> Maybe a -> Maybe a #

min :: Maybe a -> Maybe a -> Maybe a #

Pretty a => Pretty (Maybe a) 
Instance details

Defined in Text.PrettyPrint.Annotated.HughesPJClass

Methods

pPrintPrec :: PrettyLevel -> Rational -> Maybe a -> Doc ann

pPrint :: Maybe a -> Doc ann

pPrintList :: PrettyLevel -> [Maybe a] -> Doc ann

Pretty a => Pretty (Maybe a) 
Instance details

Defined in Text.PrettyPrint.HughesPJClass

Methods

pPrintPrec :: PrettyLevel -> Rational -> Maybe a -> Doc

pPrint :: Maybe a -> Doc

pPrintList :: PrettyLevel -> [Maybe a] -> Doc

SingI ('Nothing :: Maybe a) 
Instance details

Defined in GHC.Generics

Methods

sing :: Sing ('Nothing :: Maybe a)

SingI a2 => SingI ('Just a2 :: Maybe a1) 
Instance details

Defined in GHC.Generics

Methods

sing :: Sing ('Just a2)

type Rep1 Maybe 
Instance details

Defined in GHC.Generics

type Rep1 Maybe = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1))
type DemoteRep (Maybe a) 
Instance details

Defined in GHC.Generics

type DemoteRep (Maybe a) = Maybe (DemoteRep a)
type Rep (Maybe a) 
Instance details

Defined in GHC.Generics

type Rep (Maybe a) = D1 ('MetaData "Maybe" "GHC.Maybe" "base" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a)))
data Sing (b :: Maybe a) 
Instance details

Defined in GHC.Generics

data Sing (b :: Maybe a) where
type Anno (Maybe Role) Source # 
Instance details

Defined in GHC.Hs.Decls

type Anno (Maybe Role) Source # 
Instance details

Defined in GHC.Hs.Decls

maybeToList :: Maybe a -> [a] #

isJust :: Maybe a -> Bool #

fromMaybe :: a -> Maybe a -> a #

mapMaybe :: (a -> Maybe b) -> [a] -> [b] #

catMaybes :: [Maybe a] -> [a] #

maybe :: b -> (a -> b) -> Maybe a -> b #

data MaybeErr err val Source #

Constructors

Succeeded val 
Failed err 

Instances

Instances details
Applicative (MaybeErr err) Source # 
Instance details

Defined in GHC.Data.Maybe

Methods

pure :: a -> MaybeErr err a #

(<*>) :: MaybeErr err (a -> b) -> MaybeErr err a -> MaybeErr err b #

liftA2 :: (a -> b -> c) -> MaybeErr err a -> MaybeErr err b -> MaybeErr err c #

(*>) :: MaybeErr err a -> MaybeErr err b -> MaybeErr err b #

(<*) :: MaybeErr err a -> MaybeErr err b -> MaybeErr err a #

Functor (MaybeErr err) Source # 
Instance details

Defined in GHC.Data.Maybe

Methods

fmap :: (a -> b) -> MaybeErr err a -> MaybeErr err b #

(<$) :: a -> MaybeErr err b -> MaybeErr err a #

Monad (MaybeErr err) Source # 
Instance details

Defined in GHC.Data.Maybe

Methods

(>>=) :: MaybeErr err a -> (a -> MaybeErr err b) -> MaybeErr err b #

(>>) :: MaybeErr err a -> MaybeErr err b -> MaybeErr err b #

return :: a -> MaybeErr err a #

failME :: err -> MaybeErr err val Source #

orElse :: Maybe a -> a -> a infixr 4 Source #

Flipped version of fromMaybe, useful for chaining.

firstJusts :: Foldable f => f (Maybe a) -> Maybe a Source #

Takes a list of Maybes and returns the first Just if there is one, or Nothing otherwise.

firstJustsM :: (Monad m, Foldable f) => f (m (Maybe a)) -> m (Maybe a) Source #

Takes computations returnings Maybes; tries each one in order. The first one to return a Just wins. Returns Nothing if all computations return Nothing.

whenIsJust :: Monad m => Maybe a -> (a -> m ()) -> m () Source #

MaybeT

newtype MaybeT (m :: Type -> Type) a #

Constructors

MaybeT 

Fields

Instances

Instances details
MonadTrans MaybeT 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

lift :: Monad m => m a -> MaybeT m a

Functor m => Generic1 (MaybeT m :: Type -> Type) 
Instance details

Defined in Control.Monad.Trans.Maybe

Associated Types

type Rep1 (MaybeT m :: Type -> Type) 
Instance details

Defined in Control.Monad.Trans.Maybe

type Rep1 (MaybeT m :: Type -> Type) = D1 ('MetaData "MaybeT" "Control.Monad.Trans.Maybe" "transformers-0.6.1.0-1fdf" 'True) (C1 ('MetaCons "MaybeT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runMaybeT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (m :.: Rec1 Maybe)))

Methods

from1 :: MaybeT m a -> Rep1 (MaybeT m) a

to1 :: Rep1 (MaybeT m) a -> MaybeT m a

Monad m => MonadFail (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

fail :: String -> MaybeT m a #

MonadFix m => MonadFix (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

mfix :: (a -> MaybeT m a) -> MaybeT m a #

MonadIO m => MonadIO (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

liftIO :: IO a -> MaybeT m a #

MonadZip m => MonadZip (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

mzip :: MaybeT m a -> MaybeT m b -> MaybeT m (a, b)

mzipWith :: (a -> b -> c) -> MaybeT m a -> MaybeT m b -> MaybeT m c

munzip :: MaybeT m (a, b) -> (MaybeT m a, MaybeT m b)

Foldable f => Foldable (MaybeT f) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

fold :: Monoid m => MaybeT f m -> m

foldMap :: Monoid m => (a -> m) -> MaybeT f a -> m #

foldMap' :: Monoid m => (a -> m) -> MaybeT f a -> m

foldr :: (a -> b -> b) -> b -> MaybeT f a -> b #

foldr' :: (a -> b -> b) -> b -> MaybeT f a -> b

foldl :: (b -> a -> b) -> b -> MaybeT f a -> b #

foldl' :: (b -> a -> b) -> b -> MaybeT f a -> b #

foldr1 :: (a -> a -> a) -> MaybeT f a -> a #

foldl1 :: (a -> a -> a) -> MaybeT f a -> a #

toList :: MaybeT f a -> [a]

null :: MaybeT f a -> Bool #

length :: MaybeT f a -> Int #

elem :: Eq a => a -> MaybeT f a -> Bool #

maximum :: Ord a => MaybeT f a -> a #

minimum :: Ord a => MaybeT f a -> a #

sum :: Num a => MaybeT f a -> a #

product :: Num a => MaybeT f a -> a #

Eq1 m => Eq1 (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

liftEq :: (a -> b -> Bool) -> MaybeT m a -> MaybeT m b -> Bool

Ord1 m => Ord1 (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

liftCompare :: (a -> b -> Ordering) -> MaybeT m a -> MaybeT m b -> Ordering

Read1 m => Read1 (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (MaybeT m a)

liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [MaybeT m a]

liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (MaybeT m a)

liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [MaybeT m a]

Show1 m => Show1 (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> MaybeT m a -> ShowS

liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [MaybeT m a] -> ShowS

Contravariant m => Contravariant (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

contramap :: (a' -> a) -> MaybeT m a -> MaybeT m a'

(>$) :: b -> MaybeT m b -> MaybeT m a

Traversable f => Traversable (MaybeT f) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

traverse :: Applicative f0 => (a -> f0 b) -> MaybeT f a -> f0 (MaybeT f b) #

sequenceA :: Applicative f0 => MaybeT f (f0 a) -> f0 (MaybeT f a) #

mapM :: Monad m => (a -> m b) -> MaybeT f a -> m (MaybeT f b) #

sequence :: Monad m => MaybeT f (m a) -> m (MaybeT f a) #

(Functor m, Monad m) => Alternative (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

empty :: MaybeT m a

(<|>) :: MaybeT m a -> MaybeT m a -> MaybeT m a

some :: MaybeT m a -> MaybeT m [a]

many :: MaybeT m a -> MaybeT m [a]

(Functor m, Monad m) => Applicative (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

pure :: a -> MaybeT m a #

(<*>) :: MaybeT m (a -> b) -> MaybeT m a -> MaybeT m b #

liftA2 :: (a -> b -> c) -> MaybeT m a -> MaybeT m b -> MaybeT m c #

(*>) :: MaybeT m a -> MaybeT m b -> MaybeT m b #

(<*) :: MaybeT m a -> MaybeT m b -> MaybeT m a #

Functor m => Functor (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

fmap :: (a -> b) -> MaybeT m a -> MaybeT m b #

(<$) :: a -> MaybeT m b -> MaybeT m a #

Monad m => Monad (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

(>>=) :: MaybeT m a -> (a -> MaybeT m b) -> MaybeT m b #

(>>) :: MaybeT m a -> MaybeT m b -> MaybeT m b #

return :: a -> MaybeT m a #

Monad m => MonadPlus (MaybeT m) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

mzero :: MaybeT m a

mplus :: MaybeT m a -> MaybeT m a -> MaybeT m a

MonadCatch m => MonadCatch (MaybeT m) 
Instance details

Defined in Control.Monad.Catch

Methods

catch :: (HasCallStack, Exception e) => MaybeT m a -> (e -> MaybeT m a) -> MaybeT m a

MonadMask m => MonadMask (MaybeT m) 
Instance details

Defined in Control.Monad.Catch

Methods

mask :: HasCallStack => ((forall a. MaybeT m a -> MaybeT m a) -> MaybeT m b) -> MaybeT m b

uninterruptibleMask :: HasCallStack => ((forall a. MaybeT m a -> MaybeT m a) -> MaybeT m b) -> MaybeT m b

generalBracket :: HasCallStack => MaybeT m a -> (a -> ExitCase b -> MaybeT m c) -> (a -> MaybeT m b) -> MaybeT m (b, c)

MonadThrow m => MonadThrow (MaybeT m) 
Instance details

Defined in Control.Monad.Catch

Methods

throwM :: (HasCallStack, Exception e) => e -> MaybeT m a

(Monad m, HasDynFlags m) => HasDynFlags (MaybeT m) Source # 
Instance details

Defined in GHC.Driver.DynFlags

Generic (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

Associated Types

type Rep (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

type Rep (MaybeT m a) = D1 ('MetaData "MaybeT" "Control.Monad.Trans.Maybe" "transformers-0.6.1.0-1fdf" 'True) (C1 ('MetaCons "MaybeT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runMaybeT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (m (Maybe a)))))

Methods

from :: MaybeT m a -> Rep (MaybeT m a) x

to :: Rep (MaybeT m a) x -> MaybeT m a

(Read1 m, Read a) => Read (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

readsPrec :: Int -> ReadS (MaybeT m a) #

readList :: ReadS [MaybeT m a] #

readPrec :: ReadPrec (MaybeT m a)

readListPrec :: ReadPrec [MaybeT m a]

(Show1 m, Show a) => Show (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

showsPrec :: Int -> MaybeT m a -> ShowS #

show :: MaybeT m a -> String #

showList :: [MaybeT m a] -> ShowS #

(Eq1 m, Eq a) => Eq (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

(==) :: MaybeT m a -> MaybeT m a -> Bool #

(/=) :: MaybeT m a -> MaybeT m a -> Bool #

(Ord1 m, Ord a) => Ord (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

Methods

compare :: MaybeT m a -> MaybeT m a -> Ordering #

(<) :: MaybeT m a -> MaybeT m a -> Bool #

(<=) :: MaybeT m a -> MaybeT m a -> Bool #

(>) :: MaybeT m a -> MaybeT m a -> Bool #

(>=) :: MaybeT m a -> MaybeT m a -> Bool #

max :: MaybeT m a -> MaybeT m a -> MaybeT m a #

min :: MaybeT m a -> MaybeT m a -> MaybeT m a #

type Rep1 (MaybeT m :: Type -> Type) 
Instance details

Defined in Control.Monad.Trans.Maybe

type Rep1 (MaybeT m :: Type -> Type) = D1 ('MetaData "MaybeT" "Control.Monad.Trans.Maybe" "transformers-0.6.1.0-1fdf" 'True) (C1 ('MetaCons "MaybeT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runMaybeT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (m :.: Rec1 Maybe)))
type Rep (MaybeT m a) 
Instance details

Defined in Control.Monad.Trans.Maybe

type Rep (MaybeT m a) = D1 ('MetaData "MaybeT" "Control.Monad.Trans.Maybe" "transformers-0.6.1.0-1fdf" 'True) (C1 ('MetaCons "MaybeT" 'PrefixI 'True) (S1 ('MetaSel ('Just "runMaybeT") 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 (m (Maybe a)))))

liftMaybeT :: Monad m => m a -> MaybeT m a Source #

tryMaybeT :: IO a -> MaybeT IO a Source #

Try performing an IO action, failing on error.