parsek-1.0.4.0: Parallel Parsing Processes

Text.ParserCombinators.Parsek.Position

Synopsis

# Documentation

guard :: Alternative f => Bool -> f () #

Conditional failure of Alternative computations. Defined by

guard True  = pure ()
guard False = empty


#### Examples

Expand

Common uses of guard include conditionally signaling an error in an error monad and conditionally rejecting the current choice in an Alternative-based parser.

As an example of signaling 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) otherwise. For example:

>>> safeDiv 4 0
Nothing
>>> safeDiv 4 2
Just 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)


(<$) :: Functor f => a -> f b -> f a infixl 4 # Replace all locations in the input with the same value. The default definition is fmap . const, but this may be overridden with a more efficient version. class Functor f => Applicative (f :: Type -> Type) where # A functor with application, providing operations to • embed pure expressions (pure), and • sequence computations and combine their results (<*> and liftA2). A minimal complete definition must include implementations of pure and of either <*> or liftA2. If it defines both, then they must behave the same as their default definitions: (<*>) = liftA2 id liftA2 f x y = f <$> x <*> y

Further, any definition must satisfy the following:

identity
pure id <*> v = v
composition
pure (.) <*> u <*> v <*> w = u <*> (v <*> w)
homomorphism
pure f <*> pure x = pure (f x)
interchange
u <*> pure y = pure ($ y) <*> u The other methods have the following default definitions, which may be overridden with equivalent specialized implementations: • u *> v = (id <$ u) <*> v
• u <* v = liftA2 const u v

As a consequence of these laws, the Functor instance for f will satisfy

• fmap f x = pure f <*> x

It may be useful to note that supposing

forall x y. p (q x y) = f x . g y

it follows from the above that

liftA2 p (liftA2 q u v) = liftA2 f u . liftA2 g v

If f is also a Monad, it should satisfy

• pure = return
• (<*>) = ap
• (*>) = (>>)

(which implies that pure and <*> satisfy the applicative functor laws).

Minimal complete definition

pure, ((<*>) | liftA2)

Methods

pure :: a -> f a #

Lift a value.

(<*>) :: f (a -> b) -> f a -> f b infixl 4 #

Sequential application.

A few functors support an implementation of <*> that is more efficient than the default one.

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

Lift a binary function to actions.

Some functors support an implementation of liftA2 that is more efficient than the default one. In particular, if fmap is an expensive operation, it is likely better to use liftA2 than to fmap over the structure and then use <*>.

(*>) :: f a -> f b -> f b infixl 4 #

Sequence actions, discarding the value of the first argument.

(<*) :: f a -> f b -> f a infixl 4 #

Sequence actions, discarding the value of the second argument.

Instances
 Since: base-2.1 Instance detailsDefined in GHC.Base Methodspure :: a -> [a] #(<*>) :: [a -> b] -> [a] -> [b] #liftA2 :: (a -> b -> c) -> [a] -> [b] -> [c] #(*>) :: [a] -> [b] -> [b] #(<*) :: [a] -> [b] -> [a] # Since: base-2.1 Instance detailsDefined in GHC.Base Methodspure :: 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 # Since: base-2.1 Instance detailsDefined in GHC.Base Methodspure :: a -> IO a #(<*>) :: IO (a -> b) -> IO a -> IO b #liftA2 :: (a -> b -> c) -> IO a -> IO b -> IO c #(*>) :: IO a -> IO b -> IO b #(<*) :: IO a -> IO b -> IO a # f '<$>' 'ZipList' xs1 '<*>' ... '<*>' 'ZipList' xsN = 'ZipList' (zipWithN f xs1 ... xsN)where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..] = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..]) = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a -> ZipList a #(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b #liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c #(*>) :: ZipList a -> ZipList b -> ZipList b #(<*) :: ZipList a -> ZipList b -> ZipList a # Since: base-4.6.0.0 Instance detailsDefined in Text.ParserCombinators.ReadP Methodspure :: a -> ReadP a #(<*>) :: ReadP (a -> b) -> ReadP a -> ReadP b #liftA2 :: (a -> b -> c) -> ReadP a -> ReadP b -> ReadP c #(*>) :: ReadP a -> ReadP b -> ReadP b #(<*) :: ReadP a -> ReadP b -> ReadP a # Since: base-4.9.0.0 Instance detailsDefined in GHC.Base Methodspure :: a -> NonEmpty a #(<*>) :: NonEmpty (a -> b) -> NonEmpty a -> NonEmpty b #liftA2 :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c #(*>) :: NonEmpty a -> NonEmpty b -> NonEmpty b #(<*) :: NonEmpty a -> NonEmpty b -> NonEmpty a # Since: base-4.5.0.0 Instance detailsDefined in Text.ParserCombinators.ReadP Methodspure :: a -> P a #(<*>) :: P (a -> b) -> P a -> P b #liftA2 :: (a -> b -> c) -> P a -> P b -> P c #(*>) :: P a -> P b -> P b #(<*) :: P a -> P b -> P a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodspure :: a -> Parser a #(<*>) :: Parser (a -> b) -> Parser a -> Parser b #liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c #(*>) :: Parser a -> Parser b -> Parser b #(<*) :: Parser a -> Parser b -> Parser a # Since: base-3.0 Instance detailsDefined in Data.Either Methodspure :: a -> Either e a #(<*>) :: Either e (a -> b) -> Either e a -> Either e b #liftA2 :: (a -> b -> c) -> Either e a -> Either e b -> Either e c #(*>) :: Either e a -> Either e b -> Either e b #(<*) :: Either e a -> Either e b -> Either e a # Monoid a => Applicative ((,) a) For tuples, the Monoid constraint on a determines how the first values merge. For example, Strings concatenate:("hello ", (+15)) <*> ("world!", 2002) ("hello world!",2017)Since: base-2.1 Instance detailsDefined in GHC.Base Methodspure :: a0 -> (a, a0) #(<*>) :: (a, a0 -> b) -> (a, a0) -> (a, b) #liftA2 :: (a0 -> b -> c) -> (a, a0) -> (a, b) -> (a, c) #(*>) :: (a, a0) -> (a, b) -> (a, b) #(<*) :: (a, a0) -> (a, b) -> (a, a0) # Monad m => Applicative (WrappedMonad m) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a -> WrappedMonad m a #(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b #liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c #(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b #(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a # Arrow a => Applicative (ArrowMonad a) Since: base-4.6.0.0 Instance detailsDefined in Control.Arrow Methodspure :: a0 -> ArrowMonad a a0 #(<*>) :: ArrowMonad a (a0 -> b) -> ArrowMonad a a0 -> ArrowMonad a b #liftA2 :: (a0 -> b -> c) -> ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a c #(*>) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a b #(<*) :: ArrowMonad a a0 -> ArrowMonad a b -> ArrowMonad a a0 # Source # Instance detailsDefined in Text.ParserCombinators.Parsek Methodspure :: a -> Parser s a #(<*>) :: Parser s (a -> b) -> Parser s a -> Parser s b #liftA2 :: (a -> b -> c) -> Parser s a -> Parser s b -> Parser s c #(*>) :: Parser s a -> Parser s b -> Parser s b #(<*) :: Parser s a -> Parser s b -> Parser s a # Arrow a => Applicative (WrappedArrow a b) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a0 -> WrappedArrow a b a0 #(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 #liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c #(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 #(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 # Monoid m => Applicative (Const m :: Type -> Type) Since: base-2.0.1 Instance detailsDefined in Data.Functor.Const Methodspure :: a -> Const m a #(<*>) :: Const m (a -> b) -> Const m a -> Const m b #liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c #(*>) :: Const m a -> Const m b -> Const m b #(<*) :: Const m a -> Const m b -> Const m a # Applicative ((->) a :: Type -> Type) Since: base-2.1 Instance detailsDefined in GHC.Base Methodspure :: a0 -> a -> a0 #(<*>) :: (a -> (a0 -> b)) -> (a -> a0) -> a -> b #liftA2 :: (a0 -> b -> c) -> (a -> a0) -> (a -> b) -> a -> c #(*>) :: (a -> a0) -> (a -> b) -> a -> b #(<*) :: (a -> a0) -> (a -> b) -> a -> a0 #

optional :: Alternative f => f a -> f (Maybe a) #

One or none.

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

Constructors

Instances
 Monad m => Monad (WrappedMonad m) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative Methods(>>=) :: WrappedMonad m a -> (a -> WrappedMonad m b) -> WrappedMonad m b #(>>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b #return :: a -> WrappedMonad m a #fail :: String -> WrappedMonad m a # Monad m => Functor (WrappedMonad m) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsfmap :: (a -> b) -> WrappedMonad m a -> WrappedMonad m b #(<$) :: a -> WrappedMonad m b -> WrappedMonad m a # Monad m => Applicative (WrappedMonad m) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a -> WrappedMonad m a #(<*>) :: WrappedMonad m (a -> b) -> WrappedMonad m a -> WrappedMonad m b #liftA2 :: (a -> b -> c) -> WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m c #(*>) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m b #(<*) :: WrappedMonad m a -> WrappedMonad m b -> WrappedMonad m a # Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsempty :: WrappedMonad m a #(<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a #some :: WrappedMonad m a -> WrappedMonad m [a] #many :: WrappedMonad m a -> WrappedMonad m [a] # Generic1 (WrappedMonad m :: Type -> Type) Instance detailsDefined in Control.Applicative Associated Typestype Rep1 (WrappedMonad m) :: k -> Type # Methodsfrom1 :: WrappedMonad m a -> Rep1 (WrappedMonad m) a #to1 :: Rep1 (WrappedMonad m) a -> WrappedMonad m a # Generic (WrappedMonad m a) Instance detailsDefined in Control.Applicative Associated Typestype Rep (WrappedMonad m a) :: Type -> Type # Methodsfrom :: WrappedMonad m a -> Rep (WrappedMonad m a) x #to :: Rep (WrappedMonad m a) x -> WrappedMonad m a # type Rep1 (WrappedMonad m :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep1 (WrappedMonad m :: Type -> Type) = D1 (MetaData "WrappedMonad" "Control.Applicative" "base" True) (C1 (MetaCons "WrapMonad" PrefixI True) (S1 (MetaSel (Just "unwrapMonad") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec1 m))) type Rep (WrappedMonad m a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep (WrappedMonad m a) = D1 (MetaData "WrappedMonad" "Control.Applicative" "base" True) (C1 (MetaCons "WrapMonad" PrefixI True) (S1 (MetaSel (Just "unwrapMonad") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (m a)))) newtype WrappedArrow (a :: Type -> Type -> Type) b c # Constructors  WrapArrow FieldsunwrapArrow :: a b c Instances  Generic1 (WrappedArrow a b :: Type -> Type) Instance detailsDefined in Control.Applicative Associated Typestype Rep1 (WrappedArrow a b) :: k -> Type # Methodsfrom1 :: WrappedArrow a b a0 -> Rep1 (WrappedArrow a b) a0 #to1 :: Rep1 (WrappedArrow a b) a0 -> WrappedArrow a b a0 # Arrow a => Functor (WrappedArrow a b) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsfmap :: (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 #(<$) :: a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 # Arrow a => Applicative (WrappedArrow a b) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a0 -> WrappedArrow a b a0 #(<*>) :: WrappedArrow a b (a0 -> b0) -> WrappedArrow a b a0 -> WrappedArrow a b b0 #liftA2 :: (a0 -> b0 -> c) -> WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b c #(*>) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b b0 #(<*) :: WrappedArrow a b a0 -> WrappedArrow a b b0 -> WrappedArrow a b a0 # (ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsempty :: WrappedArrow a b a0 #(<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 #some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] #many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] # Generic (WrappedArrow a b c) Instance detailsDefined in Control.Applicative Associated Typestype Rep (WrappedArrow a b c) :: Type -> Type # Methodsfrom :: WrappedArrow a b c -> Rep (WrappedArrow a b c) x #to :: Rep (WrappedArrow a b c) x -> WrappedArrow a b c # type Rep1 (WrappedArrow a b :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep1 (WrappedArrow a b :: Type -> Type) = D1 (MetaData "WrappedArrow" "Control.Applicative" "base" True) (C1 (MetaCons "WrapArrow" PrefixI True) (S1 (MetaSel (Just "unwrapArrow") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec1 (a b)))) type Rep (WrappedArrow a b c) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep (WrappedArrow a b c) = D1 (MetaData "WrappedArrow" "Control.Applicative" "base" True) (C1 (MetaCons "WrapArrow" PrefixI True) (S1 (MetaSel (Just "unwrapArrow") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (a b c))))

newtype ZipList a #

Lists, but with an Applicative functor based on zipping.

Constructors

 ZipList FieldsgetZipList :: [a]
Instances
 Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsfmap :: (a -> b) -> ZipList a -> ZipList b #(<$) :: a -> ZipList b -> ZipList a # f '<$>' 'ZipList' xs1 '<*>' ... '<*>' 'ZipList' xsN = 'ZipList' (zipWithN f xs1 ... xsN)where zipWithN refers to the zipWith function of the appropriate arity (zipWith, zipWith3, zipWith4, ...). For example:(\a b c -> stimes c [a, b]) <$> ZipList "abcd" <*> ZipList "567" <*> ZipList [1..] = ZipList (zipWith3 (\a b c -> stimes c [a, b]) "abcd" "567" [1..]) = ZipList {getZipList = ["a5","b6b6","c7c7c7"]}Since: base-2.1 Instance detailsDefined in Control.Applicative Methodspure :: a -> ZipList a #(<*>) :: ZipList (a -> b) -> ZipList a -> ZipList b #liftA2 :: (a -> b -> c) -> ZipList a -> ZipList b -> ZipList c #(*>) :: ZipList a -> ZipList b -> ZipList b #(<*) :: ZipList a -> ZipList b -> ZipList a # Since: base-4.9.0.0 Instance detailsDefined in Control.Applicative Methodsfold :: Monoid m => ZipList m -> m #foldMap :: Monoid m => (a -> m) -> ZipList a -> m #foldr :: (a -> b -> b) -> b -> ZipList a -> b #foldr' :: (a -> b -> b) -> b -> ZipList a -> b #foldl :: (b -> a -> b) -> b -> ZipList a -> b #foldl' :: (b -> a -> b) -> b -> ZipList a -> b #foldr1 :: (a -> a -> a) -> ZipList a -> a #foldl1 :: (a -> a -> a) -> ZipList a -> a #toList :: ZipList a -> [a] #null :: ZipList a -> Bool #length :: ZipList a -> Int #elem :: Eq a => a -> ZipList a -> Bool #maximum :: Ord a => ZipList a -> a #minimum :: Ord a => ZipList a -> a #sum :: Num a => ZipList a -> a #product :: Num a => ZipList a -> a # Since: base-4.9.0.0 Instance detailsDefined in Data.Traversable Methodstraverse :: Applicative f => (a -> f b) -> ZipList a -> f (ZipList b) #sequenceA :: Applicative f => ZipList (f a) -> f (ZipList a) #mapM :: Monad m => (a -> m b) -> ZipList a -> m (ZipList b) #sequence :: Monad m => ZipList (m a) -> m (ZipList a) # Since: base-4.11.0.0 Instance detailsDefined in Control.Applicative Methods(<|>) :: ZipList a -> ZipList a -> ZipList a #some :: ZipList a -> ZipList [a] #many :: ZipList a -> ZipList [a] # Eq a => Eq (ZipList a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative Methods(==) :: ZipList a -> ZipList a -> Bool #(/=) :: ZipList a -> ZipList a -> Bool # Ord a => Ord (ZipList a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative Methodscompare :: ZipList a -> ZipList a -> Ordering #(<) :: ZipList a -> ZipList a -> Bool #(<=) :: ZipList a -> ZipList a -> Bool #(>) :: ZipList a -> ZipList a -> Bool #(>=) :: ZipList a -> ZipList a -> Bool #max :: ZipList a -> ZipList a -> ZipList a #min :: ZipList a -> ZipList a -> ZipList a # Read a => Read (ZipList a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative MethodsreadsPrec :: Int -> ReadS (ZipList a) # Show a => Show (ZipList a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative MethodsshowsPrec :: Int -> ZipList a -> ShowS #show :: ZipList a -> String #showList :: [ZipList a] -> ShowS # Instance detailsDefined in Control.Applicative Associated Typestype Rep (ZipList a) :: Type -> Type # Methodsfrom :: ZipList a -> Rep (ZipList a) x #to :: Rep (ZipList a) x -> ZipList a # Instance detailsDefined in Control.Applicative Associated Typestype Rep1 ZipList :: k -> Type # Methodsfrom1 :: ZipList a -> Rep1 ZipList a #to1 :: Rep1 ZipList a -> ZipList a # type Rep (ZipList a) Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep (ZipList a) = D1 (MetaData "ZipList" "Control.Applicative" "base" True) (C1 (MetaCons "ZipList" PrefixI True) (S1 (MetaSel (Just "getZipList") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 [a]))) type Rep1 ZipList Since: base-4.7.0.0 Instance detailsDefined in Control.Applicative type Rep1 ZipList = D1 (MetaData "ZipList" "Control.Applicative" "base" True) (C1 (MetaCons "ZipList" PrefixI True) (S1 (MetaSel (Just "getZipList") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec1 []))) newtype Const a (b :: k) :: forall k. Type -> k -> Type # The Const functor. Constructors  Const FieldsgetConst :: a Instances  Generic1 (Const a :: k -> Type) Instance detailsDefined in Data.Functor.Const Associated Typestype Rep1 (Const a) :: k -> Type # Methodsfrom1 :: Const a a0 -> Rep1 (Const a) a0 #to1 :: Rep1 (Const a) a0 -> Const a a0 # Functor (Const m :: Type -> Type) Since: base-2.1 Instance detailsDefined in Data.Functor.Const Methodsfmap :: (a -> b) -> Const m a -> Const m b #(<$) :: a -> Const m b -> Const m a # Monoid m => Applicative (Const m :: Type -> Type) Since: base-2.0.1 Instance detailsDefined in Data.Functor.Const Methodspure :: a -> Const m a #(<*>) :: Const m (a -> b) -> Const m a -> Const m b #liftA2 :: (a -> b -> c) -> Const m a -> Const m b -> Const m c #(*>) :: Const m a -> Const m b -> Const m b #(<*) :: Const m a -> Const m b -> Const m a # Foldable (Const m :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Data.Functor.Const Methodsfold :: Monoid m0 => Const m m0 -> m0 #foldMap :: Monoid m0 => (a -> m0) -> Const m a -> m0 #foldr :: (a -> b -> b) -> b -> Const m a -> b #foldr' :: (a -> b -> b) -> b -> Const m a -> b #foldl :: (b -> a -> b) -> b -> Const m a -> b #foldl' :: (b -> a -> b) -> b -> Const m a -> b #foldr1 :: (a -> a -> a) -> Const m a -> a #foldl1 :: (a -> a -> a) -> Const m a -> a #toList :: Const m a -> [a] #null :: Const m a -> Bool #length :: Const m a -> Int #elem :: Eq a => a -> Const m a -> Bool #maximum :: Ord a => Const m a -> a #minimum :: Ord a => Const m a -> a #sum :: Num a => Const m a -> a #product :: Num a => Const m a -> a # Traversable (Const m :: Type -> Type) Since: base-4.7.0.0 Instance detailsDefined in Data.Traversable Methodstraverse :: Applicative f => (a -> f b) -> Const m a -> f (Const m b) #sequenceA :: Applicative f => Const m (f a) -> f (Const m a) #mapM :: Monad m0 => (a -> m0 b) -> Const m a -> m0 (Const m b) #sequence :: Monad m0 => Const m (m0 a) -> m0 (Const m a) # Bounded a => Bounded (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodsminBound :: Const a b #maxBound :: Const a b # Enum a => Enum (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodssucc :: Const a b -> Const a b #pred :: Const a b -> Const a b #toEnum :: Int -> Const a b #fromEnum :: Const a b -> Int #enumFrom :: Const a b -> [Const a b] #enumFromThen :: Const a b -> Const a b -> [Const a b] #enumFromTo :: Const a b -> Const a b -> [Const a b] #enumFromThenTo :: Const a b -> Const a b -> Const a b -> [Const a b] # Eq a => Eq (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methods(==) :: Const a b -> Const a b -> Bool #(/=) :: Const a b -> Const a b -> Bool # Floating a => Floating (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodspi :: Const a b #exp :: Const a b -> Const a b #log :: Const a b -> Const a b #sqrt :: Const a b -> Const a b #(**) :: Const a b -> Const a b -> Const a b #logBase :: Const a b -> Const a b -> Const a b #sin :: Const a b -> Const a b #cos :: Const a b -> Const a b #tan :: Const a b -> Const a b #asin :: Const a b -> Const a b #acos :: Const a b -> Const a b #atan :: Const a b -> Const a b #sinh :: Const a b -> Const a b #cosh :: Const a b -> Const a b #tanh :: Const a b -> Const a b #asinh :: Const a b -> Const a b #acosh :: Const a b -> Const a b #atanh :: Const a b -> Const a b #log1p :: Const a b -> Const a b #expm1 :: Const a b -> Const a b #log1pexp :: Const a b -> Const a b #log1mexp :: Const a b -> Const a b # Fractional a => Fractional (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methods(/) :: Const a b -> Const a b -> Const a b #recip :: Const a b -> Const a b #fromRational :: Rational -> Const a b # Integral a => Integral (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodsquot :: Const a b -> Const a b -> Const a b #rem :: Const a b -> Const a b -> Const a b #div :: Const a b -> Const a b -> Const a b #mod :: Const a b -> Const a b -> Const a b #quotRem :: Const a b -> Const a b -> (Const a b, Const a b) #divMod :: Const a b -> Const a b -> (Const a b, Const a b) #toInteger :: Const a b -> Integer # Num a => Num (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methods(+) :: Const a b -> Const a b -> Const a b #(-) :: Const a b -> Const a b -> Const a b #(*) :: Const a b -> Const a b -> Const a b #negate :: Const a b -> Const a b #abs :: Const a b -> Const a b #signum :: Const a b -> Const a b #fromInteger :: Integer -> Const a b # Ord a => Ord (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodscompare :: Const a b -> Const a b -> Ordering #(<) :: Const a b -> Const a b -> Bool #(<=) :: Const a b -> Const a b -> Bool #(>) :: Const a b -> Const a b -> Bool #(>=) :: Const a b -> Const a b -> Bool #max :: Const a b -> Const a b -> Const a b #min :: Const a b -> Const a b -> Const a b # Read a => Read (Const a b) This instance would be equivalent to the derived instances of the Const newtype if the runConst field were removedSince: base-4.8.0.0 Instance detailsDefined in Data.Functor.Const MethodsreadsPrec :: Int -> ReadS (Const a b) #readList :: ReadS [Const a b] #readPrec :: ReadPrec (Const a b) #readListPrec :: ReadPrec [Const a b] # Real a => Real (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodstoRational :: Const a b -> Rational # RealFloat a => RealFloat (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodsfloatRadix :: Const a b -> Integer #floatDigits :: Const a b -> Int #floatRange :: Const a b -> (Int, Int) #decodeFloat :: Const a b -> (Integer, Int) #encodeFloat :: Integer -> Int -> Const a b #exponent :: Const a b -> Int #significand :: Const a b -> Const a b #scaleFloat :: Int -> Const a b -> Const a b #isNaN :: Const a b -> Bool #isInfinite :: Const a b -> Bool #isDenormalized :: Const a b -> Bool #isNegativeZero :: Const a b -> Bool #isIEEE :: Const a b -> Bool #atan2 :: Const a b -> Const a b -> Const a b # RealFrac a => RealFrac (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodsproperFraction :: Integral b0 => Const a b -> (b0, Const a b) #truncate :: Integral b0 => Const a b -> b0 #round :: Integral b0 => Const a b -> b0 #ceiling :: Integral b0 => Const a b -> b0 #floor :: Integral b0 => Const a b -> b0 # Show a => Show (Const a b) This instance would be equivalent to the derived instances of the Const newtype if the runConst field were removedSince: base-4.8.0.0 Instance detailsDefined in Data.Functor.Const MethodsshowsPrec :: Int -> Const a b -> ShowS #show :: Const a b -> String #showList :: [Const a b] -> ShowS # Ix a => Ix (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodsrange :: (Const a b, Const a b) -> [Const a b] #index :: (Const a b, Const a b) -> Const a b -> Int #unsafeIndex :: (Const a b, Const a b) -> Const a b -> IntinRange :: (Const a b, Const a b) -> Const a b -> Bool #rangeSize :: (Const a b, Const a b) -> Int #unsafeRangeSize :: (Const a b, Const a b) -> Int Generic (Const a b) Instance detailsDefined in Data.Functor.Const Associated Typestype Rep (Const a b) :: Type -> Type # Methodsfrom :: Const a b -> Rep (Const a b) x #to :: Rep (Const a b) x -> Const a b # Semigroup a => Semigroup (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methods(<>) :: Const a b -> Const a b -> Const a b #sconcat :: NonEmpty (Const a b) -> Const a b #stimes :: Integral b0 => b0 -> Const a b -> Const a b # Monoid a => Monoid (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methodsmempty :: Const a b #mappend :: Const a b -> Const a b -> Const a b #mconcat :: [Const a b] -> Const a b # Storable a => Storable (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodssizeOf :: Const a b -> Int #alignment :: Const a b -> Int #peekElemOff :: Ptr (Const a b) -> Int -> IO (Const a b) #pokeElemOff :: Ptr (Const a b) -> Int -> Const a b -> IO () #peekByteOff :: Ptr b0 -> Int -> IO (Const a b) #pokeByteOff :: Ptr b0 -> Int -> Const a b -> IO () #peek :: Ptr (Const a b) -> IO (Const a b) #poke :: Ptr (Const a b) -> Const a b -> IO () # Bits a => Bits (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const Methods(.&.) :: Const a b -> Const a b -> Const a b #(.|.) :: Const a b -> Const a b -> Const a b #xor :: Const a b -> Const a b -> Const a b #complement :: Const a b -> Const a b #shift :: Const a b -> Int -> Const a b #rotate :: Const a b -> Int -> Const a b #zeroBits :: Const a b #bit :: Int -> Const a b #setBit :: Const a b -> Int -> Const a b #clearBit :: Const a b -> Int -> Const a b #complementBit :: Const a b -> Int -> Const a b #testBit :: Const a b -> Int -> Bool #bitSizeMaybe :: Const a b -> Maybe Int #bitSize :: Const a b -> Int #isSigned :: Const a b -> Bool #shiftL :: Const a b -> Int -> Const a b #unsafeShiftL :: Const a b -> Int -> Const a b #shiftR :: Const a b -> Int -> Const a b #unsafeShiftR :: Const a b -> Int -> Const a b #rotateL :: Const a b -> Int -> Const a b #rotateR :: Const a b -> Int -> Const a b #popCount :: Const a b -> Int # FiniteBits a => FiniteBits (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const MethodsfiniteBitSize :: Const a b -> Int #countLeadingZeros :: Const a b -> Int #countTrailingZeros :: Const a b -> Int # type Rep1 (Const a :: k -> Type) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const type Rep1 (Const a :: k -> Type) = D1 (MetaData "Const" "Data.Functor.Const" "base" True) (C1 (MetaCons "Const" PrefixI True) (S1 (MetaSel (Just "getConst") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a))) type Rep (Const a b) Since: base-4.9.0.0 Instance detailsDefined in Data.Functor.Const type Rep (Const a b) = D1 (MetaData "Const" "Data.Functor.Const" "base" True) (C1 (MetaCons "Const" PrefixI True) (S1 (MetaSel (Just "getConst") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 a)))

forM_ :: (Foldable t, Monad m) => t a -> (a -> m b) -> m () #

forM_ is mapM_ with its arguments flipped. For a version that doesn't ignore the results see forM.

As of base 4.8.0.0, forM_ is just for_, specialized to Monad.

(<$>) :: Functor f => (a -> b) -> f a -> f b infixl 4 # An infix synonym for fmap. The name of this operator is an allusion to $. Note the similarities between their types:

 ($) :: (a -> b) -> a -> b (<$>) :: Functor f => (a -> b) -> f a -> f b

Whereas $ is function application, <$> is function application lifted over a Functor.

#### Examples

Expand

Convert from a Maybe Int to a Maybe String using show:

>>> show <$> Nothing Nothing >>> show <$> Just 3
Just "3"


Convert from an Either Int Int to an Either Int String using show:

>>> show <$> Left 17 Left 17 >>> show <$> Right 17
Right "17"


Double each element of a list:

>>> (*2) <$> [1,2,3] [2,4,6]  Apply even to the second element of a pair: >>> even <$> (2,2)
(2,True)


ap :: Monad m => m (a -> b) -> m a -> m b #

In many situations, the liftM operations can be replaced by uses of ap, which promotes function application.

return f ap x1 ap ... ap xn

is equivalent to

liftMn f x1 x2 ... xn

liftA3 :: Applicative f => (a -> b -> c -> d) -> f a -> f b -> f c -> f d #

Lift a ternary function to actions.

liftA :: Applicative f => (a -> b) -> f a -> f b #

Lift a function to actions. This function may be used as a value for fmap in a Functor instance.

(<**>) :: Applicative f => f a -> f (a -> b) -> f b infixl 4 #

A variant of <*> with the arguments reversed.

class Applicative f => Alternative (f :: Type -> Type) where #

A monoid on applicative functors.

If defined, some and many should be the least solutions of the equations:

• some v = (:) <$> v <*> many v • many v = some v <|> pure [] Minimal complete definition Methods empty :: f a # The identity of <|> (<|>) :: f a -> f a -> f a infixl 3 # An associative binary operation some :: f a -> f [a] # One or more. many :: f a -> f [a] # Zero or more. Instances  Since: base-2.1 Instance detailsDefined in GHC.Base Methodsempty :: [a] #(<|>) :: [a] -> [a] -> [a] #some :: [a] -> [[a]] #many :: [a] -> [[a]] # Since: base-2.1 Instance detailsDefined in GHC.Base Methodsempty :: Maybe a #(<|>) :: Maybe a -> Maybe a -> Maybe a #some :: Maybe a -> Maybe [a] #many :: Maybe a -> Maybe [a] # Since: base-4.9.0.0 Instance detailsDefined in GHC.Base Methodsempty :: IO a #(<|>) :: IO a -> IO a -> IO a #some :: IO a -> IO [a] #many :: IO a -> IO [a] # Since: base-4.11.0.0 Instance detailsDefined in Control.Applicative Methods(<|>) :: ZipList a -> ZipList a -> ZipList a #some :: ZipList a -> ZipList [a] #many :: ZipList a -> ZipList [a] # Since: base-4.6.0.0 Instance detailsDefined in Text.ParserCombinators.ReadP Methodsempty :: ReadP a #(<|>) :: ReadP a -> ReadP a -> ReadP a #some :: ReadP a -> ReadP [a] #many :: ReadP a -> ReadP [a] # Since: base-4.5.0.0 Instance detailsDefined in Text.ParserCombinators.ReadP Methodsempty :: P a #(<|>) :: P a -> P a -> P a #some :: P a -> P [a] #many :: P a -> P [a] # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsempty :: Parser a #(<|>) :: Parser a -> Parser a -> Parser a #some :: Parser a -> Parser [a] #many :: Parser a -> Parser [a] # Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsempty :: WrappedMonad m a #(<|>) :: WrappedMonad m a -> WrappedMonad m a -> WrappedMonad m a #some :: WrappedMonad m a -> WrappedMonad m [a] #many :: WrappedMonad m a -> WrappedMonad m [a] # Since: base-4.6.0.0 Instance detailsDefined in Control.Arrow Methodsempty :: ArrowMonad a a0 #(<|>) :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 #some :: ArrowMonad a a0 -> ArrowMonad a [a0] #many :: ArrowMonad a a0 -> ArrowMonad a [a0] # Source # Instance detailsDefined in Text.ParserCombinators.Parsek Methodsempty :: Parser s a #(<|>) :: Parser s a -> Parser s a -> Parser s a #some :: Parser s a -> Parser s [a] #many :: Parser s a -> Parser s [a] # (ArrowZero a, ArrowPlus a) => Alternative (WrappedArrow a b) Since: base-2.1 Instance detailsDefined in Control.Applicative Methodsempty :: WrappedArrow a b a0 #(<|>) :: WrappedArrow a b a0 -> WrappedArrow a b a0 -> WrappedArrow a b a0 #some :: WrappedArrow a b a0 -> WrappedArrow a b [a0] #many :: WrappedArrow a b a0 -> WrappedArrow a b [a0] # class (Alternative m, Monad m) => MonadPlus (m :: Type -> Type) where # Monads that also support choice and failure. Minimal complete definition Nothing Methods mzero :: m a # The identity of mplus. It should also satisfy the equations mzero >>= f = mzero v >> mzero = mzero The default definition is mzero = empty  mplus :: m a -> m a -> m a # An associative operation. The default definition is mplus = (<|>)  Instances  Since: base-2.1 Instance detailsDefined in GHC.Base Methodsmzero :: [a] #mplus :: [a] -> [a] -> [a] # Since: base-2.1 Instance detailsDefined in GHC.Base Methodsmzero :: Maybe a #mplus :: Maybe a -> Maybe a -> Maybe a # Since: base-4.9.0.0 Instance detailsDefined in GHC.Base Methodsmzero :: IO a #mplus :: IO a -> IO a -> IO a # Since: base-2.1 Instance detailsDefined in Text.ParserCombinators.ReadP Methodsmzero :: ReadP a #mplus :: ReadP a -> ReadP a -> ReadP a # Since: base-2.1 Instance detailsDefined in Text.ParserCombinators.ReadP Methodsmzero :: P a #mplus :: P a -> P a -> P a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsmzero :: Parser a #mplus :: Parser a -> Parser a -> Parser a # (ArrowApply a, ArrowPlus a) => MonadPlus (ArrowMonad a) Since: base-4.6.0.0 Instance detailsDefined in Control.Arrow Methodsmzero :: ArrowMonad a a0 #mplus :: ArrowMonad a a0 -> ArrowMonad a a0 -> ArrowMonad a a0 # Source # Instance detailsDefined in Text.ParserCombinators.Parsek Methodsmzero :: Parser s a #mplus :: Parser s a -> Parser s a -> Parser s a # class (Monad p, Alternative p) => IsParser p where Source # Parser class Associated Types type SymbolOf p Source # Methods Arguments  :: (SymbolOf p -> Bool) -> p (SymbolOf p) accept a symbol satisfying a given predicate Arguments  :: p [SymbolOf p] access the stream of symbols from the current point Arguments  :: String -> p a -> p a label the parser (<<|>) infixr 3 Source # Arguments  :: p a -> p a -> p a Left-biased choice. Instances  Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Associated Types Methodslabel :: String -> Parser a -> Parser a Source #(<<|>) :: Parser a -> Parser a -> Parser a Source # Source # Instance detailsDefined in Text.ParserCombinators.Parsek Associated Typestype SymbolOf (Parser s) :: Type Source # Methodssatisfy :: (SymbolOf (Parser s) -> Bool) -> Parser s (SymbolOf (Parser s)) Source #look :: Parser s [SymbolOf (Parser s)] Source #label :: String -> Parser s a -> Parser s a Source #(<<|>) :: Parser s a -> Parser s a -> Parser s a Source # (<?>) :: IsParser p => p a -> String -> p a infix 2 Source # Label a parser char :: (IsParser p, Eq (SymbolOf p), Show (SymbolOf p)) => SymbolOf p -> p (SymbolOf p) Source # noneOf :: (IsParser p, SymbolOf p ~# Char) => [Char] -> p Char Source # oneOf :: (IsParser p, SymbolOf p ~# Char) => [Char] -> p Char Source # spaces :: (IsParser p, SymbolOf p ~# Char) => p () Source # space :: (IsParser p, SymbolOf p ~# Char) => p Char Source # tab :: (IsParser p, Eq (SymbolOf p), Show (SymbolOf p), SymbolOf p ~# Char) => p Char Source # upper :: (IsParser p, SymbolOf p ~# Char) => p Char Source # lower :: (IsParser p, SymbolOf p ~# Char) => p Char Source # digit :: (IsParser p, SymbolOf p ~# Char) => p Char Source # choice :: Alternative f => [f a] -> f a Source # option :: Alternative f => a -> f a -> f a Source # between :: Applicative m => m x -> m y -> m a -> m a Source # manyGreedy :: IsParser m => m a -> m [a] Source # Greedy repetition: match as many occurences as possible of the argument. skipMany1 :: Alternative f => f a -> f () Source # skipMany :: Alternative f => f a -> f () Source # sepBy :: Alternative f => f a1 -> f a2 -> f [a1] Source # sepBy1 :: Alternative f => f a1 -> f a2 -> f [a1] Source # count :: Applicative m => Int -> m a -> m [a] Source # chainr :: (Alternative f, Monad f) => f a -> f (a -> a -> a) -> a -> f a Source # chainl :: (Alternative f, Monad f) => f a -> f (a -> a -> a) -> a -> f a Source # chainr1 :: (Monad f, Alternative f) => f t -> f (t -> t -> t) -> f t Source # chainl1 :: (Alternative m, Monad m) => m b -> m (b -> b -> b) -> m b Source # munch :: IsParser m => (SymbolOf m -> Bool) -> m [SymbolOf m] Source # munch1 :: IsParser m => (SymbolOf m -> Bool) -> m [SymbolOf m] Source # endOfFile :: IsParser p => p () Source # type ParseResult s r = Either (Err s) r Source # type ParseMethod s a r = P s a -> [s] -> ParseResult s r Source # type Expect s = [(String, Maybe s)] Source # An intersection (nesting) of things currently expected mapErrR :: (s -> s') -> ParseResult s r -> ParseResult s' r Source # data SourcePos Source # Constructors  Loc FieldssourceName :: !FilePath sourceLine :: !Int sourceCol :: !Int EOF Instances  Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methods Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methods Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position MethodsshowList :: [SourcePos] -> ShowS # data Parser a Source # Instances  Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methods(>>=) :: Parser a -> (a -> Parser b) -> Parser b #(>>) :: Parser a -> Parser b -> Parser b #return :: a -> Parser a #fail :: String -> Parser a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsfmap :: (a -> b) -> Parser a -> Parser b #(<$) :: a -> Parser b -> Parser a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsfail :: String -> Parser a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodspure :: a -> Parser a #(<*>) :: Parser (a -> b) -> Parser a -> Parser b #liftA2 :: (a -> b -> c) -> Parser a -> Parser b -> Parser c #(*>) :: Parser a -> Parser b -> Parser b #(<*) :: Parser a -> Parser b -> Parser a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsempty :: Parser a #(<|>) :: Parser a -> Parser a -> Parser a #some :: Parser a -> Parser [a] #many :: Parser a -> Parser [a] # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Methodsmzero :: Parser a #mplus :: Parser a -> Parser a -> Parser a # Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position Associated Types Methodslabel :: String -> Parser a -> Parser a Source #(<<|>) :: Parser a -> Parser a -> Parser a Source # type SymbolOf Parser Source # Instance detailsDefined in Text.ParserCombinators.Parsek.Position type SymbolOf Parser = Char

parse :: FilePath -> Parser a -> (forall s. ParseMethod s a r) -> String -> ParseResult SourcePos r Source #