| Copyright | (c) 2025 Patrick Brisbin |
|---|---|
| License | AGPL-3 |
| Maintainer | [email protected] |
| Stability | experimental |
| Portability | POSIX |
| Safe Haskell | None |
| Language | GHC2021 |
Data.JSON.Patch.Prelude
Description
Synopsis
- module Prelude
- data NonEmpty a
- class Generic a
- data Text
- unless :: Applicative f => Bool -> f () -> f ()
- void :: Functor f => f a -> f ()
- fromMaybe :: a -> Maybe a -> a
- when :: Applicative f => Bool -> f () -> f ()
- (<|>) :: Alternative f => f a -> f a -> f a
- data Vector a
- guard :: Alternative f => Bool -> f ()
- bimap :: Bifunctor p => (a -> b) -> (c -> d) -> p a c -> p b d
- first :: Bifunctor p => (a -> b) -> p a c -> p b c
- second :: Bifunctor p => (b -> c) -> p a b -> p a c
- class (Typeable e, Show e) => Exception e where
- toException :: e -> SomeException
- fromException :: SomeException -> Maybe e
- displayException :: e -> String
- asum :: (Foldable t, Alternative f) => t (f a) -> f a
- foldM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b
- nonEmpty :: [a] -> Maybe (NonEmpty a)
- pack :: String -> Text
- unpack :: Text -> String
- note :: e -> Maybe a -> Either e a
Documentation
module Prelude
Non-empty (and non-strict) list type.
Since: base-4.9.0.0
Instances
| FromJSON1 NonEmpty | |||||
Defined in Data.Aeson.Types.FromJSON | |||||
| ToJSON1 NonEmpty | |||||
Defined in Data.Aeson.Types.ToJSON Methods liftToJSON :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> NonEmpty a -> Value # liftToJSONList :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> [NonEmpty a] -> Value # liftToEncoding :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> NonEmpty a -> Encoding # liftToEncodingList :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> [NonEmpty a] -> Encoding # liftOmitField :: (a -> Bool) -> NonEmpty a -> Bool # | |||||
| MonadFix NonEmpty | Since: base-4.9.0.0 | ||||
Defined in Control.Monad.Fix | |||||
| MonadZip NonEmpty | Since: base-4.9.0.0 | ||||
| Foldable NonEmpty | Since: base-4.9.0.0 | ||||
Defined in Data.Foldable Methods fold :: Monoid m => NonEmpty m -> m # foldMap :: Monoid m => (a -> m) -> NonEmpty a -> m # foldMap' :: Monoid m => (a -> m) -> NonEmpty a -> m # foldr :: (a -> b -> b) -> b -> NonEmpty a -> b # foldr' :: (a -> b -> b) -> b -> NonEmpty a -> b # foldl :: (b -> a -> b) -> b -> NonEmpty a -> b # foldl' :: (b -> a -> b) -> b -> NonEmpty a -> b # foldr1 :: (a -> a -> a) -> NonEmpty a -> a # foldl1 :: (a -> a -> a) -> NonEmpty a -> a # elem :: Eq a => a -> NonEmpty a -> Bool # maximum :: Ord a => NonEmpty a -> a # minimum :: Ord a => NonEmpty a -> a # | |||||
| Foldable1 NonEmpty | Since: base-4.18.0.0 | ||||
Defined in Data.Foldable1 Methods fold1 :: Semigroup m => NonEmpty m -> m # foldMap1 :: Semigroup m => (a -> m) -> NonEmpty a -> m # foldMap1' :: Semigroup m => (a -> m) -> NonEmpty a -> m # toNonEmpty :: NonEmpty a -> NonEmpty a # maximum :: Ord a => NonEmpty a -> a # minimum :: Ord a => NonEmpty a -> a # foldrMap1 :: (a -> b) -> (a -> b -> b) -> NonEmpty a -> b # foldlMap1' :: (a -> b) -> (b -> a -> b) -> NonEmpty a -> b # foldlMap1 :: (a -> b) -> (b -> a -> b) -> NonEmpty a -> b # foldrMap1' :: (a -> b) -> (a -> b -> b) -> NonEmpty a -> b # | |||||
| Eq1 NonEmpty | Since: base-4.10.0.0 | ||||
| Ord1 NonEmpty | Since: base-4.10.0.0 | ||||
Defined in Data.Functor.Classes | |||||
| Read1 NonEmpty | Since: base-4.10.0.0 | ||||
Defined in Data.Functor.Classes | |||||
| Show1 NonEmpty | Since: base-4.10.0.0 | ||||
| Traversable NonEmpty | Since: base-4.9.0.0 | ||||
| Applicative NonEmpty | Since: base-4.9.0.0 | ||||
| Functor NonEmpty | Since: base-4.9.0.0 | ||||
| Monad NonEmpty | Since: base-4.9.0.0 | ||||
| NFData1 NonEmpty | Since: deepseq-1.4.3.0 | ||||
Defined in Control.DeepSeq | |||||
| Hashable1 NonEmpty | Since: hashable-1.3.1.0 | ||||
Defined in Data.Hashable.Class | |||||
| Generic1 NonEmpty | |||||
Defined in GHC.Generics Associated Types
| |||||
| Lift a => Lift (NonEmpty a :: Type) | Since: template-haskell-2.15.0.0 | ||||
| Each Int (NonEmpty a) (NonEmpty b) a b |
| ||||
Defined in Optics.Each.Core | |||||
| FromJSON a => FromJSON (NonEmpty a) | |||||
Defined in Data.Aeson.Types.FromJSON | |||||
| ToJSON a => ToJSON (NonEmpty a) | |||||
| Data a => Data (NonEmpty a) | Since: base-4.9.0.0 | ||||
Defined in Data.Data Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> NonEmpty a -> c (NonEmpty a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (NonEmpty a) # toConstr :: NonEmpty a -> Constr # dataTypeOf :: NonEmpty a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (NonEmpty a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (NonEmpty a)) # gmapT :: (forall b. Data b => b -> b) -> NonEmpty a -> NonEmpty a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> NonEmpty a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> NonEmpty a -> r # gmapQ :: (forall d. Data d => d -> u) -> NonEmpty a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> NonEmpty a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> NonEmpty a -> m (NonEmpty a) # | |||||
| Semigroup (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Generic (NonEmpty a) | |||||
Defined in GHC.Generics Associated Types
| |||||
| IsList (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Read a => Read (NonEmpty a) | Since: base-4.11.0.0 | ||||
| Show a => Show (NonEmpty a) | Since: base-4.11.0.0 | ||||
| NFData a => NFData (NonEmpty a) | Since: deepseq-1.4.2.0 | ||||
Defined in Control.DeepSeq | |||||
| Eq a => Eq (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Ord a => Ord (NonEmpty a) | Since: base-4.9.0.0 | ||||
| Hashable a => Hashable (NonEmpty a) | |||||
Defined in Data.Hashable.Class | |||||
| Ixed (NonEmpty a) | |||||
| type Rep1 NonEmpty | Since: base-4.6.0.0 | ||||
Defined in GHC.Generics type Rep1 NonEmpty = D1 ('MetaData "NonEmpty" "GHC.Base" "base" 'False) (C1 ('MetaCons ":|" ('InfixI 'RightAssociative 5) 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) Par1 :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec1 []))) | |||||
| type Rep (NonEmpty a) | Since: base-4.6.0.0 | ||||
Defined in GHC.Generics type Rep (NonEmpty a) = D1 ('MetaData "NonEmpty" "GHC.Base" "base" 'False) (C1 ('MetaCons ":|" ('InfixI 'RightAssociative 5) 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 a) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [a]))) | |||||
| type Item (NonEmpty a) | |||||
Defined in GHC.IsList | |||||
| type Index (NonEmpty a) | |||||
Defined in Optics.At.Core | |||||
| type IxKind (NonEmpty a) | |||||
Defined in Optics.At.Core | |||||
| type IxValue (NonEmpty a) | |||||
Defined in Optics.At.Core | |||||
Representable types of kind *.
This class is derivable in GHC with the DeriveGeneric flag on.
A Generic instance must satisfy the following laws:
from.to≡idto.from≡id
Instances
A space efficient, packed, unboxed Unicode text type.
Instances
| FromJSON Text | |
Defined in Data.Aeson.Types.FromJSON | |
| FromJSONKey Text | |
Defined in Data.Aeson.Types.FromJSON | |
| ToJSON Text | |
| ToJSONKey Text | |
Defined in Data.Aeson.Types.ToJSON | |
| AsJSON Text | |
| AsNumber Text | |
| AsValue Text | |
| IsKey Text | |
| Hashable Text | |
Defined in Data.Hashable.Class | |
| type Item Text | |
| type Index Text | |
| type IxKind Text | |
Defined in Optics.At | |
| type IxValue Text | |
unless :: Applicative f => Bool -> f () -> f () #
The reverse of when.
void :: Functor f => f a -> f () #
void valueIO action.
Examples
Replace the contents of a Maybe Int
>>>void NothingNothing>>>void (Just 3)Just ()
Replace the contents of an Either Int IntEither Int ()
>>>void (Left 8675309)Left 8675309>>>void (Right 8675309)Right ()
Replace every element of a list with unit:
>>>void [1,2,3][(),(),()]
Replace the second element of a pair with unit:
>>>void (1,2)(1,())
Discard the result of an IO action:
>>>mapM print [1,2]1 2 [(),()]>>>void $ mapM print [1,2]1 2
fromMaybe :: a -> Maybe a -> a #
The fromMaybe function takes a default value and a Maybe
value. If the Maybe is Nothing, it returns the default value;
otherwise, it returns the value contained in the Maybe.
Examples
Basic usage:
>>>fromMaybe "" (Just "Hello, World!")"Hello, World!"
>>>fromMaybe "" Nothing""
Read an integer from a string using readMaybe. If we fail to
parse an integer, we want to return 0 by default:
>>>import Text.Read ( readMaybe )>>>fromMaybe 0 (readMaybe "5")5>>>fromMaybe 0 (readMaybe "")0
when :: Applicative f => Bool -> f () -> f () #
Conditional execution of Applicative expressions. For example,
when debug (putStrLn "Debugging")
will output the string Debugging if the Boolean value debug
is True, and otherwise do nothing.
(<|>) :: Alternative f => f a -> f a -> f a infixl 3 #
An associative binary operation
Instances
| FromJSON1 Vector | |
Defined in Data.Aeson.Types.FromJSON | |
| ToJSON1 Vector | |
Defined in Data.Aeson.Types.ToJSON Methods liftToJSON :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> Vector a -> Value # liftToJSONList :: (a -> Bool) -> (a -> Value) -> ([a] -> Value) -> [Vector a] -> Value # liftToEncoding :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> Vector a -> Encoding # liftToEncodingList :: (a -> Bool) -> (a -> Encoding) -> ([a] -> Encoding) -> [Vector a] -> Encoding # liftOmitField :: (a -> Bool) -> Vector a -> Bool # | |
| MonadFail Vector | |
Defined in Data.Vector | |
| MonadFix Vector | |
Defined in Data.Vector | |
| MonadZip Vector | |
| Foldable Vector | |
Defined in Data.Vector Methods fold :: Monoid m => Vector m -> m # foldMap :: Monoid m => (a -> m) -> Vector a -> m # foldMap' :: Monoid m => (a -> m) -> Vector a -> m # foldr :: (a -> b -> b) -> b -> Vector a -> b # foldr' :: (a -> b -> b) -> b -> Vector a -> b # foldl :: (b -> a -> b) -> b -> Vector a -> b # foldl' :: (b -> a -> b) -> b -> Vector a -> b # foldr1 :: (a -> a -> a) -> Vector a -> a # foldl1 :: (a -> a -> a) -> Vector a -> a # elem :: Eq a => a -> Vector a -> Bool # maximum :: Ord a => Vector a -> a # minimum :: Ord a => Vector a -> a # | |
| Eq1 Vector | |
| Ord1 Vector | |
Defined in Data.Vector | |
| Read1 Vector | |
Defined in Data.Vector | |
| Show1 Vector | |
| Traversable Vector | |
| Alternative Vector | |
| Applicative Vector | |
| Functor Vector | |
| Monad Vector | |
| MonadPlus Vector | |
| NFData1 Vector | |
Defined in Data.Vector | |
| Vector Vector a | |
Defined in Data.Vector Methods basicUnsafeFreeze :: Mutable Vector s a -> ST s (Vector a) basicUnsafeThaw :: Vector a -> ST s (Mutable Vector s a) basicLength :: Vector a -> Int basicUnsafeSlice :: Int -> Int -> Vector a -> Vector a basicUnsafeIndexM :: Vector a -> Int -> Box a basicUnsafeCopy :: Mutable Vector s a -> Vector a -> ST s () | |
| FromJSON a => FromJSON (Vector a) | |
Defined in Data.Aeson.Types.FromJSON | |
| ToJSON a => ToJSON (Vector a) | |
| Data a => Data (Vector a) | |
Defined in Data.Vector Methods gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Vector a -> c (Vector a) # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Vector a) # toConstr :: Vector a -> Constr # dataTypeOf :: Vector a -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Vector a)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Vector a)) # gmapT :: (forall b. Data b => b -> b) -> Vector a -> Vector a # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Vector a -> r # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Vector a -> r # gmapQ :: (forall d. Data d => d -> u) -> Vector a -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Vector a -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Vector a -> m (Vector a) # | |
| Monoid (Vector a) | |
| Semigroup (Vector a) | |
| IsList (Vector a) | |
| Read a => Read (Vector a) | |
| Show a => Show (Vector a) | |
| NFData a => NFData (Vector a) | |
Defined in Data.Vector | |
| Eq a => Eq (Vector a) | |
| Ord a => Ord (Vector a) | |
Defined in Data.Vector | |
| type Mutable Vector | |
Defined in Data.Vector type Mutable Vector = MVector | |
| type Item (Vector a) | |
Defined in Data.Vector | |
| type Index (Vector a) | |
| type IxKind (Vector a) | |
Defined in Optics.At | |
| type IxValue (Vector a) | |
guard :: Alternative f => Bool -> f () #
Conditional failure of Alternative computations. Defined by
guard True =pure() guard False =empty
Examples
Common uses of guard include conditionally signalling an error in
an error monad and conditionally rejecting the current choice in an
Alternative-based parser.
As an example of signalling an error in the error monad Maybe,
consider a safe division function safeDiv x y that returns
Nothing when the denominator y is zero and Just (x `div`
y)
>>>safeDiv 4 0Nothing
>>>safeDiv 4 2Just 2
A definition of safeDiv using guards, but not guard:
safeDiv :: Int -> Int -> Maybe Int
safeDiv x y | y /= 0 = Just (x `div` y)
| otherwise = Nothing
A definition of safeDiv using guard and Monad do-notation:
safeDiv :: Int -> Int -> Maybe Int safeDiv x y = do guard (y /= 0) return (x `div` y)
class (Typeable e, Show e) => Exception e where #
Any type that you wish to throw or catch as an exception must be an
instance of the Exception class. The simplest case is a new exception
type directly below the root:
data MyException = ThisException | ThatException
deriving Show
instance Exception MyExceptionThe default method definitions in the Exception class do what we need
in this case. You can now throw and catch ThisException and
ThatException as exceptions:
*Main> throw ThisException `catch` \e -> putStrLn ("Caught " ++ show (e :: MyException))
Caught ThisException
In more complicated examples, you may wish to define a whole hierarchy of exceptions:
---------------------------------------------------------------------
-- Make the root exception type for all the exceptions in a compiler
data SomeCompilerException = forall e . Exception e => SomeCompilerException e
instance Show SomeCompilerException where
show (SomeCompilerException e) = show e
instance Exception SomeCompilerException
compilerExceptionToException :: Exception e => e -> SomeException
compilerExceptionToException = toException . SomeCompilerException
compilerExceptionFromException :: Exception e => SomeException -> Maybe e
compilerExceptionFromException x = do
SomeCompilerException a <- fromException x
cast a
---------------------------------------------------------------------
-- Make a subhierarchy for exceptions in the frontend of the compiler
data SomeFrontendException = forall e . Exception e => SomeFrontendException e
instance Show SomeFrontendException where
show (SomeFrontendException e) = show e
instance Exception SomeFrontendException where
toException = compilerExceptionToException
fromException = compilerExceptionFromException
frontendExceptionToException :: Exception e => e -> SomeException
frontendExceptionToException = toException . SomeFrontendException
frontendExceptionFromException :: Exception e => SomeException -> Maybe e
frontendExceptionFromException x = do
SomeFrontendException a <- fromException x
cast a
---------------------------------------------------------------------
-- Make an exception type for a particular frontend compiler exception
data MismatchedParentheses = MismatchedParentheses
deriving Show
instance Exception MismatchedParentheses where
toException = frontendExceptionToException
fromException = frontendExceptionFromExceptionWe can now catch a MismatchedParentheses exception as
MismatchedParentheses, SomeFrontendException or
SomeCompilerException, but not other types, e.g. IOException:
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: MismatchedParentheses))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: SomeFrontendException))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: SomeCompilerException))
Caught MismatchedParentheses
*Main> throw MismatchedParentheses `catch` \e -> putStrLn ("Caught " ++ show (e :: IOException))
*** Exception: MismatchedParentheses
Minimal complete definition
Nothing
Methods
toException :: e -> SomeException #
fromException :: SomeException -> Maybe e #
displayException :: e -> String #
Render this exception value in a human-friendly manner.
Default implementation: show
Since: base-4.8.0.0
Instances
| Exception AesonException | |
Defined in Data.Aeson.Types.Internal Methods toException :: AesonException -> SomeException # | |
| Exception NestedAtomically | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: NestedAtomically -> SomeException # | |
| Exception NoMatchingContinuationPrompt | Since: base-4.18 |
Defined in Control.Exception.Base | |
| Exception NoMethodError | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: NoMethodError -> SomeException # fromException :: SomeException -> Maybe NoMethodError # displayException :: NoMethodError -> String # | |
| Exception NonTermination | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: NonTermination -> SomeException # | |
| Exception PatternMatchFail | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: PatternMatchFail -> SomeException # | |
| Exception RecConError | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: RecConError -> SomeException # fromException :: SomeException -> Maybe RecConError # displayException :: RecConError -> String # | |
| Exception RecSelError | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: RecSelError -> SomeException # fromException :: SomeException -> Maybe RecSelError # displayException :: RecSelError -> String # | |
| Exception RecUpdError | Since: base-4.0 |
Defined in Control.Exception.Base Methods toException :: RecUpdError -> SomeException # fromException :: SomeException -> Maybe RecUpdError # displayException :: RecUpdError -> String # | |
| Exception TypeError | Since: base-4.9.0.0 |
Defined in Control.Exception.Base Methods toException :: TypeError -> SomeException # fromException :: SomeException -> Maybe TypeError # displayException :: TypeError -> String # | |
| Exception Dynamic | Since: base-4.0.0.0 |
Defined in Data.Dynamic Methods toException :: Dynamic -> SomeException # fromException :: SomeException -> Maybe Dynamic # displayException :: Dynamic -> String # | |
| Exception Void | Since: base-4.8.0.0 |
Defined in GHC.Exception.Type Methods toException :: Void -> SomeException # fromException :: SomeException -> Maybe Void # displayException :: Void -> String # | |
| Exception ErrorCall | Since: base-4.0.0.0 |
Defined in GHC.Exception Methods toException :: ErrorCall -> SomeException # fromException :: SomeException -> Maybe ErrorCall # displayException :: ErrorCall -> String # | |
| Exception ArithException | Since: base-4.0.0.0 |
Defined in GHC.Exception.Type Methods toException :: ArithException -> SomeException # | |
| Exception SomeException | Since: base-3.0 |
Defined in GHC.Exception.Type Methods toException :: SomeException -> SomeException # fromException :: SomeException -> Maybe SomeException # displayException :: SomeException -> String # | |
| Exception AllocationLimitExceeded | Since: base-4.8.0.0 |
Defined in GHC.IO.Exception | |
| Exception ArrayException | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception Methods toException :: ArrayException -> SomeException # | |
| Exception AssertionFailed | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception Methods toException :: AssertionFailed -> SomeException # | |
| Exception AsyncException | Since: base-4.7.0.0 |
Defined in GHC.IO.Exception Methods toException :: AsyncException -> SomeException # | |
| Exception BlockedIndefinitelyOnMVar | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Exception BlockedIndefinitelyOnSTM | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception | |
| Exception CompactionFailed | Since: base-4.10.0.0 |
Defined in GHC.IO.Exception Methods toException :: CompactionFailed -> SomeException # | |
| Exception Deadlock | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception Methods toException :: Deadlock -> SomeException # fromException :: SomeException -> Maybe Deadlock # displayException :: Deadlock -> String # | |
| Exception ExitCode | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception Methods toException :: ExitCode -> SomeException # fromException :: SomeException -> Maybe ExitCode # displayException :: ExitCode -> String # | |
| Exception FixIOException | Since: base-4.11.0.0 |
Defined in GHC.IO.Exception Methods toException :: FixIOException -> SomeException # | |
| Exception IOException | Since: base-4.1.0.0 |
Defined in GHC.IO.Exception Methods toException :: IOException -> SomeException # fromException :: SomeException -> Maybe IOException # displayException :: IOException -> String # | |
| Exception SomeAsyncException | Since: base-4.7.0.0 |
Defined in GHC.IO.Exception Methods toException :: SomeAsyncException -> SomeException # fromException :: SomeException -> Maybe SomeAsyncException # | |
| Exception IOPortException | |
Defined in GHC.IOPort Methods toException :: IOPortException -> SomeException # fromException :: SomeException -> Maybe IOPortException # displayException :: IOPortException -> String # | |
| Exception Timeout | Since: base-4.7.0.0 |
Defined in System.Timeout Methods toException :: Timeout -> SomeException # fromException :: SomeException -> Maybe Timeout # displayException :: Timeout -> String # | |
| Exception SizeOverflowException | |
Defined in Data.ByteString.Internal.Type | |
| Exception PatchError Source # | |
Defined in Data.JSON.Patch.Error Methods toException :: PatchError -> SomeException # fromException :: SomeException -> Maybe PatchError # displayException :: PatchError -> String # | |
| Exception UnicodeException | |
Defined in Data.Text.Encoding.Error Methods toException :: UnicodeException -> SomeException # | |
asum :: (Foldable t, Alternative f) => t (f a) -> f a #
The sum of a collection of actions using (<|>), generalizing concat.
asum is just like msum, but generalised to Alternative.
Examples
Basic usage:
>>>asum [Just "Hello", Nothing, Just "World"]Just "Hello"
foldM :: (Foldable t, Monad m) => (b -> a -> m b) -> b -> t a -> m b #
The foldM function is analogous to foldl, except that its result is
encapsulated in a monad. Note that foldM works from left-to-right over
the list arguments. This could be an issue where ( and the `folded
function' are not commutative.>>)
foldM f a1 [x1, x2, ..., xm] == do a2 <- f a1 x1 a3 <- f a2 x2 ... f am xm
If right-to-left evaluation is required, the input list should be reversed.