Agda.Utils.Maybe.Strict

A strict version of the Maybe type.

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

Copyright : (c) 2006-2007 Roman Leshchinskiy (c) 2013 Simon Meier License : BSD-style (see the file LICENSE)

Copyright : (c) 2014 Andreas Abel

Documentation

module Data.Strict.Maybe

toStrict :: Maybe a -> Maybe a

toLazy :: Maybe a -> Maybe a

listToMaybe :: [a] -> Maybe a

Analogous to listToMaybe in Data.Maybe.

maybeToList :: Maybe a -> [a]

Analogous to maybeToList in Data.Maybe.

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

Analogous to catMaybes in Data.Maybe.

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

Analogous to mapMaybe in Data.Maybe.

Collection operations.

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

unionWith for collections of size <= 1.

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

Unzipping a list of length <= 1.

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

Filtering a singleton list.

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

Conditionals and loops.

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

Version of mapMaybe with different argument ordering.

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

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

Monads and Maybe.

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

Monadic version of maybe.

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

Monadic version of fromMaybe.

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

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

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

caseMaybeM with flipped branches.

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

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

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

caseMaybeM without the Nothing case.

Orphan instances

Foldable Maybe

Methods

fold :: Monoid m => Maybe m -> 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

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)

Data a => Data (Maybe a)

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 :: (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)

Associated Types

type Rep (Maybe a) :: * -> *

Methods

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

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

Monoid a => Semigroup (Maybe a)

Methods

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

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

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

Monoid a => Monoid (Maybe a)

Methods

mempty :: Maybe a

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

mconcat :: [Maybe a] -> Maybe a

Binary a => Binary (Maybe a)

Methods

put :: Maybe a -> Put

get :: Get (Maybe a)

putList :: [Maybe a] -> Put

NFData a => NFData (Maybe a)

Methods

rnf :: Maybe a -> ()

Null (Maybe a)

Methods

empty :: Maybe a

null :: Maybe a -> Bool