Safe Haskell	None
Language	Haskell2010

Agda.Utils.Maybe.Strict

Contents

Orphan instances

Description

A strict version of the Maybe type.

Import qualified, as in import qualified Agda.Utils.Maybe.Strict as Strict

Synopsis

data Maybe a
- = Nothing
- | Just !a
catMaybes :: [Maybe a] -> [a]
fromMaybe :: a -> Maybe a -> a
listToMaybe :: [a] -> Maybe a
maybeToList :: Maybe a -> [a]
maybe :: b -> (a -> b) -> Maybe a -> b
isNothing :: Maybe a -> Bool
mapMaybe :: (a -> Maybe b) -> [a] -> [b]
fromJust :: Maybe a -> a
isJust :: Maybe a -> Bool
class Strict lazy strict | lazy -> strict, strict -> lazy where
- toStrict :: lazy -> strict
- toLazy :: strict -> lazy
caseMaybeM :: Monad m => m (Maybe a) -> m b -> (a -> m b) -> m b
fromMaybeM :: Monad m => m a -> m (Maybe a) -> m a
forMaybe :: [a] -> (a -> Maybe b) -> [b]
filterMaybe :: (a -> Bool) -> a -> Maybe a
whenJust :: Monad m => Maybe a -> (a -> m ()) -> m ()
unionMaybeWith :: (a -> a -> a) -> Maybe a -> Maybe a -> Maybe a
unzipMaybe :: Maybe (a, b) -> (Maybe a, Maybe b)
caseMaybe :: Maybe a -> b -> (a -> b) -> b
maybeM :: Monad m => m b -> (a -> m b) -> m (Maybe a) -> m b
ifJustM :: Monad m => m (Maybe a) -> (a -> m b) -> m b -> m b
whenJustM :: Monad m => m (Maybe a) -> (a -> m ()) -> m ()

Documentation

data Maybe a #

Constructors

Nothing
Just !a

Instances

Instances details

EncodeTCM Range Source #

Instance details

Defined in Agda.Interaction.JSONTop

Methods

encodeTCM :: Range -> TCM Value Source #

Pretty TopLevelModuleName Source #

Instance details

Defined in Agda.Syntax.TopLevelModuleName

Methods

pretty :: TopLevelModuleName -> Doc Source #

prettyPrec :: Int -> TopLevelModuleName -> Doc Source #

prettyList :: [TopLevelModuleName] -> Doc Source #

HasRange Interval Source #

Instance details

Defined in Agda.Syntax.Position

Methods

getRange :: Interval -> Range Source #

HasRange Range Source #

Instance details

Defined in Agda.Syntax.Position

Methods

getRange :: Range -> Range Source #

KillRange Range Source #

Instance details

Defined in Agda.Syntax.Position

Methods

killRange :: KillRangeT Range Source #

SetRange Range Source #

Instance details

Defined in Agda.Syntax.Position

Methods

setRange :: Range -> Range -> Range Source #

FreshName Range Source #

Instance details

Defined in Agda.TypeChecking.Monad.Base

Methods

freshName_ :: MonadFresh NameId m => Range -> m Name Source #

PrettyTCM Range Source #

Instance details

Defined in Agda.TypeChecking.Pretty

Methods

prettyTCM :: MonadPretty m => Range -> m Doc Source #

PrettyTCM TopLevelModuleName Source #

Instance details

Defined in Agda.TypeChecking.Pretty

Methods

prettyTCM :: MonadPretty m => TopLevelModuleName -> m Doc Source #

EmbPrj Range Source #

Ranges are always deserialised as noRange.

Instance details

Defined in Agda.TypeChecking.Serialise.Instances.Common

Methods

icode :: Range -> S Int32 Source #

icod_ :: Range -> S Int32 Source #

value :: Int32 -> R Range Source #

EmbPrj TopLevelModuleName Source #

Instance details

Defined in Agda.TypeChecking.Serialise.Instances.Common

Methods

icode :: TopLevelModuleName -> S Int32 Source #

icod_ :: TopLevelModuleName -> S Int32 Source #

value :: Int32 -> R TopLevelModuleName Source #

Subst Range Source #

Instance details

Defined in Agda.TypeChecking.Substitute

Associated Types

type SubstArg Range
Instance details Defined in Agda.TypeChecking.Substitute type SubstArg Range = Term

Methods

applySubst :: Substitution' (SubstArg Range) -> Range -> Range Source #

Sized TopLevelModuleName Source #

Instance details

Defined in Agda.Syntax.TopLevelModuleName

Methods

size :: TopLevelModuleName -> Int Source #

natSize :: TopLevelModuleName -> Peano Source #

Eq1 Maybe

Instance details

Defined in Data.Strict.Maybe

Methods

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

Ord1 Maybe

Instance details

Defined in Data.Strict.Maybe

Methods

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

Read1 Maybe

Instance details

Defined in Data.Strict.Maybe

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.Strict.Maybe

Methods

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

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

NFData Interval

Instance details

Defined in Agda.Syntax.Position

Methods

rnf :: Interval -> ()

NFData Position

Instance details

Defined in Agda.Syntax.Position

Methods

rnf :: Position -> ()

NFData1 Maybe

Instance details

Defined in Data.Strict.Maybe

Methods

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

Applicative Maybe

Note that strict Maybe is an Applicative only modulo strictness. The laws only hold in the strict semantics. Eg. pure f * pure _|_ = _|_, but according to the laws for Applicative it should be pure (f _|_). We ignore this issue here, it applies also to Foldable and Traversable.

Instance details

Defined in Agda.Utils.Maybe.Strict

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 Data.Strict.Maybe

Methods

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

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

Foldable Maybe

Instance details

Defined in Data.Strict.Maybe

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

Traversable Maybe

Instance details

Defined in Data.Strict.Maybe

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)

Hashable1 Maybe

Instance details

Defined in Data.Strict.Maybe

Methods

liftHashWithSalt :: (Int -> a -> Int) -> Int -> Maybe a -> Int

FromJSON1 Maybe

Instance details

Defined in Data.Aeson.Types.FromJSON

Methods

liftParseJSON :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser (Maybe a) #

liftParseJSONList :: Maybe a -> (Value -> Parser a) -> (Value -> Parser [a]) -> Value -> Parser [Maybe a] #

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

ToJSON Range Source #

Instance details

Defined in Agda.Interaction.JSONTop

Methods

toJSON :: Range -> Value #

toEncoding :: Range -> Encoding #

toJSONList :: [Range] -> Value #

toEncodingList :: [Range] -> Encoding #

omitField :: Range -> Bool #

ToJSON1 Maybe

Instance details

Defined in Data.Aeson.Types.ToJSON

Methods

liftToJSON :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> Maybe a -> Value #

liftToJSONList :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> [Maybe a] -> Value #

liftToEncoding :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> Maybe a -> Encoding #

liftToEncodingList :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> [Maybe a] -> Encoding #

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

LensClosure MetaInfo Range Source #

Instance details

Defined in Agda.TypeChecking.Monad.Base

Methods

lensClosure :: Lens' MetaInfo (Closure Range) Source #

LensClosure MetaVariable Range Source #

Instance details

Defined in Agda.TypeChecking.Monad.Base

Methods

lensClosure :: Lens' MetaVariable (Closure Range) Source #

Generic1 Maybe

Instance details

Defined in Data.Strict.Maybe

Associated Types

type Rep1 Maybe
Instance details Defined in Data.Strict.Maybe type Rep1 Maybe = D1 ('MetaData "Maybe" "Data.Strict.Maybe" "strct-0.5.1-73fd598e" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) Par1))

Methods

from1 :: Maybe a -> Rep1 Maybe a

to1 :: Rep1 Maybe a -> Maybe a

Pretty a => Pretty (Interval' (Maybe a)) Source #

Instance details

Defined in Agda.Syntax.Common.Pretty

Methods

pretty :: Interval' (Maybe a) -> Doc Source #

prettyPrec :: Int -> Interval' (Maybe a) -> Doc Source #

prettyList :: [Interval' (Maybe a)] -> Doc Source #

Pretty a => Pretty (Position' (Maybe a)) Source #

Instance details

Defined in Agda.Syntax.Common.Pretty

Methods

pretty :: Position' (Maybe a) -> Doc Source #

prettyPrec :: Int -> Position' (Maybe a) -> Doc Source #

prettyList :: [Position' (Maybe a)] -> Doc Source #

Pretty a => Pretty (Range' (Maybe a)) Source #

Instance details

Defined in Agda.Syntax.Common.Pretty

Methods

pretty :: Range' (Maybe a) -> Doc Source #

prettyPrec :: Int -> Range' (Maybe a) -> Doc Source #

prettyList :: [Range' (Maybe a)] -> Doc Source #

NamesIn a => NamesIn (Maybe a) Source #

Instance details

Defined in Agda.Syntax.Internal.Names

Methods

namesAndMetasIn' :: Monoid m => (Either QName MetaId -> m) -> Maybe a -> m Source #

HasRange (TopLevelModuleName' Range) Source #

Instance details

Defined in Agda.Syntax.Position

Methods

getRange :: TopLevelModuleName' Range -> Range Source #

KillRange (TopLevelModuleName' Range) Source #

Instance details

Defined in Agda.Syntax.Position

Methods

killRange :: KillRangeT (TopLevelModuleName' Range) Source #

KillRange a => KillRange (Maybe a) Source #

Instance details

Defined in Agda.Syntax.Position

Methods

killRange :: KillRangeT (Maybe a) Source #

SetRange (TopLevelModuleName' Range) Source #

Instance details

Defined in Agda.Syntax.Position

Methods

setRange :: Range -> TopLevelModuleName' Range -> TopLevelModuleName' Range Source #

Instantiate t => Instantiate (Maybe t) Source #

Instance details

Defined in Agda.TypeChecking.Reduce

Methods

instantiate' :: Maybe t -> ReduceM (Maybe t) Source #

InstantiateFull t => InstantiateFull (Maybe t) Source #

Instance details

Defined in Agda.TypeChecking.Reduce

Methods

instantiateFull' :: Maybe t -> ReduceM (Maybe t) Source #

Normalise t => Normalise (Maybe t) Source #

Instance details

Defined in Agda.TypeChecking.Reduce

Methods

normalise' :: Maybe t -> ReduceM (Maybe t) Source #

Simplify t => Simplify (Maybe t) Source #

Instance details

Defined in Agda.TypeChecking.Reduce

Methods

simplify' :: Maybe t -> ReduceM (Maybe t)

EmbPrj a => EmbPrj (Maybe a) Source #

Instance details

Defined in Agda.TypeChecking.Serialise.Instances.Common

Methods

icode :: Maybe a -> S Int32 Source #

icod_ :: Maybe a -> S Int32 Source #

value :: Int32 -> R (Maybe a) Source #

Apply t => Apply (Maybe t) Source #

Instance details

Defined in Agda.TypeChecking.Substitute

Methods

apply :: Maybe t -> Args -> Maybe t Source #

applyE :: Maybe t -> Elims -> Maybe t Source #

Null (Maybe a) Source #

Instance details

Defined in Agda.Utils.Maybe.Strict

Methods

empty :: Maybe a Source #

null :: Maybe a -> Bool Source #

Binary a => Binary (Maybe a)

Instance details

Defined in Data.Strict.Maybe

Methods

put :: Maybe a -> Put

get :: Get (Maybe a)

putList :: [Maybe a] -> Put

NFData a => NFData (Maybe a)

Instance details

Defined in Data.Strict.Maybe

Methods

rnf :: Maybe a -> ()

Semigroup a => Monoid (Maybe a)

Instance details

Defined in Data.Strict.Maybe

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 Data.Strict.Maybe

Methods

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

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

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

Data a => Data (Maybe a)

Instance details

Defined in Data.Strict.Maybe

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)

Generic (Maybe a)

Instance details

Defined in Data.Strict.Maybe

Associated Types

type Rep (Maybe a)
Instance details Defined in Data.Strict.Maybe type Rep (Maybe a) = D1 ('MetaData "Maybe" "Data.Strict.Maybe" "strct-0.5.1-73fd598e" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 a)))

Methods

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

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

Read a => Read (Maybe a)

Instance details

Defined in Data.Strict.Maybe

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 Data.Strict.Maybe

Methods

showsPrec :: Int -> Maybe a -> ShowS

show :: Maybe a -> String

showList :: [Maybe a] -> ShowS

Eq a => Eq (Maybe a)

Instance details

Defined in Data.Strict.Maybe

Methods

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

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

Ord a => Ord (Maybe a)

Instance details

Defined in Data.Strict.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

Hashable a => Hashable (Maybe a)

Instance details

Defined in Data.Strict.Maybe

Methods

hashWithSalt :: Int -> Maybe a -> Int

hash :: Maybe a -> Int

FromJSON a => FromJSON (Maybe a)

Instance details

Defined in Data.Aeson.Types.FromJSON

Methods

parseJSON :: Value -> Parser (Maybe a) #

parseJSONList :: Value -> Parser [Maybe a] #

omittedField :: Maybe (Maybe a) #

ToJSON a => ToJSON (Maybe a)

Instance details

Defined in Data.Aeson.Types.ToJSON

Methods

toJSON :: Maybe a -> Value #

toEncoding :: Maybe a -> Encoding #

toJSONList :: [Maybe a] -> Value #

toEncodingList :: [Maybe a] -> Encoding #

omitField :: Maybe a -> Bool #

Strict (Maybe a) (Maybe a)

Instance details

Defined in Data.Strict.Classes

Methods

toStrict :: Maybe a -> Maybe a #

toLazy :: Maybe a -> Maybe a #

FreshName (Range, String) Source #

Instance details

Defined in Agda.TypeChecking.Monad.Base

Methods

freshName_ :: MonadFresh NameId m => (Range, String) -> m Name Source #

type SubstArg Range Source #

Instance details

Defined in Agda.TypeChecking.Substitute

type SubstArg Range = Term

type Rep1 Maybe

Instance details

Defined in Data.Strict.Maybe

type Rep1 Maybe = D1 ('MetaData "Maybe" "Data.Strict.Maybe" "strct-0.5.1-73fd598e" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) Par1))

type Rep (Maybe a)

Instance details

Defined in Data.Strict.Maybe

type Rep (Maybe a) = D1 ('MetaData "Maybe" "Data.Strict.Maybe" "strct-0.5.1-73fd598e" 'False) (C1 ('MetaCons "Nothing" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Just" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'SourceStrict 'DecidedStrict) (Rec0 a)))

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

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

listToMaybe :: [a] -> Maybe a #

maybeToList :: Maybe a -> [a] #

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

isNothing :: Maybe a -> Bool #

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

fromJust :: Maybe a -> a #

isJust :: Maybe a -> Bool #

class Strict lazy strict | lazy -> strict, strict -> lazy where #

Methods

toStrict :: lazy -> strict #

toLazy :: strict -> lazy #

Instances

Instances details

Strict ByteString ByteString
Instance details Defined in Data.Strict.Classes Methods toStrict :: ByteString -> ByteString # toLazy :: ByteString -> ByteString #
Strict Text Text
Instance details Defined in Data.Strict.Classes Methods toStrict :: Text -> Text # toLazy :: Text -> Text #
Strict (Maybe a) (Maybe a)
Instance details Defined in Data.Strict.Classes Methods toStrict :: Maybe a -> Maybe a # toLazy :: Maybe a -> Maybe a #
Strict (ST s a) (ST s a)
Instance details Defined in Data.Strict.Classes Methods toStrict :: ST s a -> ST s a # toLazy :: ST s a -> ST s a #
Strict (Either a b) (Either a b)
Instance details Defined in Data.Strict.Classes Methods toStrict :: Either a b -> Either a b # toLazy :: Either a b -> Either a b #
Strict (These a b) (These a b)
Instance details Defined in Data.Strict.Classes Methods toStrict :: These a b -> These a b # toLazy :: These a b -> These a b #
Strict (a, b) (Pair a b)
Instance details Defined in Data.Strict.Classes Methods toStrict :: (a, b) -> Pair a b # toLazy :: Pair a b -> (a, b) #
Strict (StateT s m a) (StateT s m a)
Instance details Defined in Data.Strict.Classes Methods toStrict :: StateT s m a -> StateT s m a # toLazy :: StateT s m a -> StateT s m a #
Strict (WriterT w m a) (WriterT w m a)
Instance details Defined in Data.Strict.Classes Methods toStrict :: WriterT w m a -> WriterT w m a # toLazy :: WriterT w m a -> WriterT w m a #
Strict (RWST r w s m a) (RWST r w s m a)
Instance details Defined in Data.Strict.Classes Methods toStrict :: RWST r w s m a -> RWST r w s m a # toLazy :: RWST r w s m a -> RWST r w s m a #

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

Monadic version of caseMaybe. That is, maybeM with a different argument ordering.

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

Monadic version of fromMaybe.

forMaybe :: [a] -> (a -> Maybe b) -> [b] Source #

Version of mapMaybe with different argument ordering.

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

Filtering a singleton list.

filterMaybe p a = listToMaybe (filter p [a])

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

A more telling name for forM for the Maybe collection type. Or: caseMaybe without the Nothing case.

unionMaybeWith :: (a -> a -> a) -> Maybe a -> Maybe a -> Maybe a Source #

unionWith for collections of size <= 1.

unzipMaybe :: Maybe (a, b) -> (Maybe a, Maybe b) Source #

Unzipping a list of length <= 1.

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

Version of maybe with different argument ordering. Often, we want to case on a Maybe, do something interesting in the Just case, but only a default action in the Nothing case. Then, the argument ordering of caseMaybe is preferable.

caseMaybe m err f = flip (maybe err) m f

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

Monadic version of maybe.

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

caseMaybeM with flipped branches.

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

caseMaybeM without the Nothing case.

Orphan instances

Applicative Maybe Source #	Note that strict Maybe is an `Applicative` only modulo strictness. The laws only hold in the strict semantics. Eg. `pure f * pure _\|_ = _\|_`, but according to the laws for `Applicative` it should be `pure (f _\|_)`. We ignore this issue here, it applies also to `Foldable` and `Traversable`.
Instance details 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
Null (Maybe a) Source #
Instance details Methods empty :: Maybe a Source # null :: Maybe a -> Bool Source #