| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Data.List.NonEmpty.Compat
Contents
Description
This backports the modern Data.Semigroup interface back to
base-4.9/GHC 8.0.
Synopsis
- data NonEmpty a = a :| [a]
- map :: (a -> b) -> NonEmpty a -> NonEmpty b
- intersperse :: a -> NonEmpty a -> NonEmpty a
- scanl :: Foldable f => (b -> a -> b) -> b -> f a -> NonEmpty b
- scanr :: Foldable f => (a -> b -> b) -> b -> f a -> NonEmpty b
- scanl1 :: (a -> a -> a) -> NonEmpty a -> NonEmpty a
- scanr1 :: (a -> a -> a) -> NonEmpty a -> NonEmpty a
- transpose :: NonEmpty (NonEmpty a) -> NonEmpty (NonEmpty a)
- sortBy :: (a -> a -> Ordering) -> NonEmpty a -> NonEmpty a
- sortWith :: Ord o => (a -> o) -> NonEmpty a -> NonEmpty a
- length :: NonEmpty a -> Int
- head :: NonEmpty a -> a
- tail :: NonEmpty a -> [a]
- last :: NonEmpty a -> a
- init :: NonEmpty a -> [a]
- (<|) :: a -> NonEmpty a -> NonEmpty a
- cons :: a -> NonEmpty a -> NonEmpty a
- uncons :: NonEmpty a -> (a, Maybe (NonEmpty a))
- unfoldr :: (a -> (b, Maybe a)) -> a -> NonEmpty b
- sort :: Ord a => NonEmpty a -> NonEmpty a
- reverse :: NonEmpty a -> NonEmpty a
- inits :: Foldable f => f a -> NonEmpty [a]
- tails :: Foldable f => f a -> NonEmpty [a]
- iterate :: (a -> a) -> a -> NonEmpty a
- repeat :: a -> NonEmpty a
- cycle :: NonEmpty a -> NonEmpty a
- unfold :: (a -> (b, Maybe a)) -> a -> NonEmpty b
- insert :: (Foldable f, Ord a) => a -> f a -> NonEmpty a
- some1 :: Alternative f => f a -> f (NonEmpty a)
- take :: Int -> NonEmpty a -> [a]
- drop :: Int -> NonEmpty a -> [a]
- splitAt :: Int -> NonEmpty a -> ([a], [a])
- takeWhile :: (a -> Bool) -> NonEmpty a -> [a]
- dropWhile :: (a -> Bool) -> NonEmpty a -> [a]
- span :: (a -> Bool) -> NonEmpty a -> ([a], [a])
- break :: (a -> Bool) -> NonEmpty a -> ([a], [a])
- filter :: (a -> Bool) -> NonEmpty a -> [a]
- partition :: (a -> Bool) -> NonEmpty a -> ([a], [a])
- group :: (Foldable f, Eq a) => f a -> [NonEmpty a]
- groupBy :: Foldable f => (a -> a -> Bool) -> f a -> [NonEmpty a]
- groupWith :: (Foldable f, Eq b) => (a -> b) -> f a -> [NonEmpty a]
- groupAllWith :: Ord b => (a -> b) -> [a] -> [NonEmpty a]
- group1 :: Eq a => NonEmpty a -> NonEmpty (NonEmpty a)
- groupBy1 :: (a -> a -> Bool) -> NonEmpty a -> NonEmpty (NonEmpty a)
- groupWith1 :: Eq b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a)
- groupAllWith1 :: Ord b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a)
- isPrefixOf :: Eq a => [a] -> NonEmpty a -> Bool
- nub :: Eq a => NonEmpty a -> NonEmpty a
- nubBy :: (a -> a -> Bool) -> NonEmpty a -> NonEmpty a
- (!!) :: NonEmpty a -> Int -> a
- zip :: NonEmpty a -> NonEmpty b -> NonEmpty (a, b)
- zipWith :: (a -> b -> c) -> NonEmpty a -> NonEmpty b -> NonEmpty c
- unzip :: Functor f => f (a, b) -> (f a, f b)
- fromList :: [a] -> NonEmpty a
- toList :: NonEmpty a -> [a]
- nonEmpty :: [a] -> Maybe (NonEmpty a)
- xor :: NonEmpty Bool -> Bool
The type of non-empty streams
Non-empty (and non-strict) list type.
Since: base-4.9.0.0
Constructors
| a :| [a] infixr 5 |
Instances
| Monad NonEmpty | Since: base-4.9.0.0 |
| Functor NonEmpty | Since: base-4.9.0.0 |
| Applicative 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 # 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 # | |
| Traversable NonEmpty | Since: base-4.9.0.0 |
| Eq a => Eq (NonEmpty a) | Since: base-4.9.0.0 |
| Ord a => Ord (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 |
| Semigroup (NonEmpty a) | Since: base-4.9.0.0 |
Non-empty stream transformations
intersperse :: a -> NonEmpty a -> NonEmpty a #
'intersperse x xs' alternates elements of the list with copies of x.
intersperse 0 (1 :| [2,3]) == 1 :| [0,2,0,3]
Basic functions
uncons :: NonEmpty a -> (a, Maybe (NonEmpty a)) #
uncons produces the first element of the stream, and a stream of the
remaining elements, if any.
inits :: Foldable f => f a -> NonEmpty [a] #
The inits function takes a stream xs and returns all the
finite prefixes of xs.
tails :: Foldable f => f a -> NonEmpty [a] #
The tails function takes a stream xs and returns all the
suffixes of xs.
Building streams
iterate :: (a -> a) -> a -> NonEmpty a #
produces the infinite sequence
of repeated applications of iterate f xf to x.
iterate f x = x :| [f x, f (f x), ..]
cycle :: NonEmpty a -> NonEmpty a #
returns the infinite repetition of cycle xsxs:
cycle (1 :| [2,3]) = 1 :| [2,3,1,2,3,...]
insert :: (Foldable f, Ord a) => a -> f a -> NonEmpty a #
inserts insert x xsx into the last position in xs where it
is still less than or equal to the next element. In particular, if the
list is sorted beforehand, the result will also be sorted.
some1 :: Alternative f => f a -> f (NonEmpty a) #
sequences some1 xx one or more times.
Extracting sublists
drop :: Int -> NonEmpty a -> [a] #
drops the first drop n xsn elements off the front of
the sequence xs.
splitAt :: Int -> NonEmpty a -> ([a], [a]) #
returns a pair consisting of the prefix of splitAt n xsxs
of length n and the remaining stream immediately following this prefix.
'splitAt' n xs == ('take' n xs, 'drop' n xs)
xs == ys ++ zs where (ys, zs) = 'splitAt' n xstakeWhile :: (a -> Bool) -> NonEmpty a -> [a] #
returns the longest prefix of the stream
takeWhile p xsxs for which the predicate p holds.
span :: (a -> Bool) -> NonEmpty a -> ([a], [a]) #
returns the longest prefix of span p xsxs that satisfies
p, together with the remainder of the stream.
'span' p xs == ('takeWhile' p xs, 'dropWhile' p xs)
xs == ys ++ zs where (ys, zs) = 'span' p xsfilter :: (a -> Bool) -> NonEmpty a -> [a] #
removes any elements from filter p xsxs that do not satisfy p.
partition :: (a -> Bool) -> NonEmpty a -> ([a], [a]) #
The partition function takes a predicate p and a stream
xs, and returns a pair of lists. The first list corresponds to the
elements of xs for which p holds; the second corresponds to the
elements of xs for which p does not hold.
'partition' p xs = ('filter' p xs, 'filter' (not . p) xs)group :: (Foldable f, Eq a) => f a -> [NonEmpty a] #
The group function takes a stream and returns a list of
streams such that flattening the resulting list is equal to the
argument. Moreover, each stream in the resulting list
contains only equal elements. For example, in list notation:
'group' $ 'cycle' "Mississippi" = "M" : "i" : "ss" : "i" : "ss" : "i" : "pp" : "i" : "M" : "i" : ...
groupAllWith :: Ord b => (a -> b) -> [a] -> [NonEmpty a] #
groupAllWith operates like groupWith, but sorts the list
first so that each equivalence class has, at most, one list in the
output
groupWith1 :: Eq b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a) #
groupWith1 is to group1 as groupWith is to group
groupAllWith1 :: Ord b => (a -> b) -> NonEmpty a -> NonEmpty (NonEmpty a) #
groupAllWith1 is to groupWith1 as groupAllWith is to groupWith
Sublist predicates
isPrefixOf :: Eq a => [a] -> NonEmpty a -> Bool #
The isPrefix function returns True if the first argument is
a prefix of the second.
"Set" operations
Indexing streams
(!!) :: NonEmpty a -> Int -> a infixl 9 #
xs !! n returns the element of the stream xs at index
n. Note that the head of the stream has index 0.
Beware: a negative or out-of-bounds index will cause an error.
Zipping and unzipping streams
zip :: NonEmpty a -> NonEmpty b -> NonEmpty (a, b) #
The zip function takes two streams and returns a stream of
corresponding pairs.
Converting to and from a list
fromList :: [a] -> NonEmpty a #
Converts a normal list to a NonEmpty stream.
Raises an error if given an empty list.