Data.Sequences

Warning: This module should be considered highly experimental.

Documentation

class (Integral (Index seq), GrowingAppend seq) => SemiSequence seq where

SemiSequence was created to share code between IsSequence and MinLen.

Semi means SemiGroup A SemiSequence can accomodate a SemiGroup such as NonEmpty or MinLen A Monoid should be able to fill out IsSequence.

SemiSequence operations maintain the same type because they all maintain the same number of elements or increase them. However, a decreasing function such as filter may change they type. For example, from NonEmpty to '[]' This type-changing function exists on NonNull as nfilter

filter and other such functions are placed in IsSequence

Associated Types

type Index seq

The type of the index of a sequence.

Methods

intersperse :: Element seq -> seq -> seq

intersperse takes an element and intersperses that element between the elements of the sequence.

> intersperse ',' "abcde"
"a,b,c,d,e"

reverse :: seq -> seq

Reverse a sequence

> reverse "hello world"
"dlrow olleh"

find :: (Element seq -> Bool) -> seq -> Maybe (Element seq)

find takes a predicate and a sequence and returns the first element in the sequence matching the predicate, or Nothing if there isn't an element that matches the predicate.

> find (== 5) [1 .. 10]
Just 5

> find (== 15) [1 .. 10]
Nothing

sortBy :: (Element seq -> Element seq -> Ordering) -> seq -> seq

Sort a sequence using an supplied element ordering function.

> let compare' x y = case compare x y of LT -> GT; EQ -> EQ; GT -> LT
> sortBy compare' [5,3,6,1,2,4]
[6,5,4,3,2,1]

cons :: Element seq -> seq -> seq

Prepend an element onto a sequence.

> 4 `cons` [1,2,3]
[4,1,2,3]

snoc :: seq -> Element seq -> seq

Append an element onto a sequence.

> [1,2,3] `snoc` 4
[1,2,3,4]

Instances

SemiSequence ByteString

SemiSequence ByteString

SemiSequence Text

SemiSequence Text

SemiSequence [a]

SemiSequence (Seq a)

SemiSequence (DList a)

SemiSequence (NonEmpty a)

SemiSequence (Vector a)

Unbox a => SemiSequence (Vector a)

Storable a => SemiSequence (Vector a)

SemiSequence seq => SemiSequence (MinLen nat seq)

singleton :: IsSequence seq => Element seq -> seq

Create a sequence from a single element.

> singleton a :: String
"a"
> singleton a :: Vector Char
fromList "a"

class (Monoid seq, MonoTraversable seq, SemiSequence seq, MonoPointed seq) => IsSequence seq where

Sequence Laws:

fromList . otoList = id
fromList (x <> y) = fromList x <> fromList y
otoList (fromList x <> fromList y) = x <> y

Minimal complete definition

Nothing

Methods

fromList :: [Element seq] -> seq

Convert a list to a sequence.

> fromList [a, b, c] :: Text
"abc"

break :: (Element seq -> Bool) -> seq -> (seq, seq)

break applies a predicate to a sequence, and returns a tuple where the first element is the longest prefix (possibly empty) of elements that do not satisfy the predicate. The second element of the tuple is the remainder of the sequence.

break p is equivalent to span (not . p)

> break (> 3) (fromList [1,2,3,4,1,2,3,4] :: Vector Int)
(fromList [1,2,3],fromList [4,1,2,3,4])

> break (< z) (fromList "abc" :: Text)
("","abc")

> break (> z) (fromList "abc" :: Text)
("abc","")

span :: (Element seq -> Bool) -> seq -> (seq, seq)

span applies a predicate to a sequence, and returns a tuple where the first element is the longest prefix (possibly empty) that does satisfy the predicate. The second element of the tuple is the remainder of the sequence.

span p xs is equivalent to (takeWhile p xs, dropWhile p xs)

> span (< 3) (fromList [1,2,3,4,1,2,3,4] :: Vector Int)
(fromList [1,2],fromList [3,4,1,2,3,4])

> span (< z) (fromList "abc" :: Text)
("abc","")

> span (< 0) 1,2,3

dropWhile :: (Element seq -> Bool) -> seq -> seq

dropWhile returns the suffix remaining after takeWhile.

> dropWhile (< 3) [1,2,3,4,5,1,2,3]
[3,4,5,1,2,3]

> dropWhile (< z) (fromList "abc" :: Text)
""

takeWhile :: (Element seq -> Bool) -> seq -> seq

takeWhile applies a predicate to a sequence, and returns the longest prefix (possibly empty) of the sequence of elements that satisfy the predicate.

> takeWhile (< 3) [1,2,3,4,5,1,2,3]
[1,2]

> takeWhile (< z) (fromList "abc" :: Text)
"abc"

splitAt :: Index seq -> seq -> (seq, seq)

splitAt n se returns a tuple where the first element is the prefix of the sequence se with length n, and the second element is the remainder of the sequence.

> splitAt 6 "Hello world!"
("Hello ","world!")

> splitAt 3 (fromList [1,2,3,4,5] :: Vector Int)
(fromList [1,2,3],fromList [4,5])

unsafeSplitAt :: Index seq -> seq -> (seq, seq)

Equivalent to splitAt.

take :: Index seq -> seq -> seq

take n returns the prefix of a sequence of length n, or the sequence itself if n > olength seq.

> take 3 "abcdefg"
"abc"
> take 4 (fromList [1,2,3,4,5,6] :: Vector Int)
fromList [1,2,3,4]

unsafeTake :: Index seq -> seq -> seq

Equivalent to take.

drop :: Index seq -> seq -> seq

drop n returns the suffix of a sequence after the first n elements, or an empty sequence if n > olength seq.

> drop 3 "abcdefg"
"defg"
> drop 4 (fromList [1,2,3,4,5,6] :: Vector Int)
fromList [5,6]

unsafeDrop :: Index seq -> seq -> seq

Equivalent to drop

partition :: (Element seq -> Bool) -> seq -> (seq, seq)

partition takes a predicate and a sequence and returns the pair of sequences of elements which do and do not satisfy the predicate.

partition p se = (filter p se, filter (not . p) se)

uncons :: seq -> Maybe (Element seq, seq)

uncons returns the tuple of the first element of a sequence and the rest of the sequence, or Nothing if the sequence is empty.

> uncons (fromList [1,2,3,4] :: Vector Int)
Just (1,fromList [2,3,4])

> uncons ([] :: [Int])
Nothing

unsnoc :: seq -> Maybe (seq, Element seq)

unsnoc returns the tuple of the init of a sequence and the last element, or Nothing if the sequence is empty.

> uncons (fromList [1,2,3,4] :: Vector Int)
Just (fromList [1,2,3],4)

> uncons ([] :: [Int])
Nothing

filter :: (Element seq -> Bool) -> seq -> seq

filter given a predicate returns a sequence of all elements that satisfy the predicate.

> filter (< 5) [1 .. 10]
[1,2,3,4]

filterM :: Monad m => (Element seq -> m Bool) -> seq -> m seq

The monadic version of filter.

replicate :: Index seq -> Element seq -> seq

replicate n x is a sequence of length n with x as the value of every element.

> replicate 10 a :: Text
"aaaaaaaaaa"

replicateM :: Monad m => Index seq -> m (Element seq) -> m seq

The monadic version of replicateM.

groupBy :: (Element seq -> Element seq -> Bool) -> seq -> [seq]

group takes a sequence and returns a list of sequences such that the concatenation of the result is equal to the argument. Each subsequence in the result contains only equal elements, using the supplied equality test.

> groupBy (==) Mississippi
[M,"i","ss","i","ss","i","pp","i"]

groupAllOn :: Eq b => (Element seq -> b) -> seq -> [seq]

Similar to standard groupBy, but operates on the whole collection, not just the consecutive items.

subsequences :: seq -> [seq]

subsequences returns a list of all subsequences of the argument.

> subsequences "abc"
["","a","b","ab","c","ac","bc","abc"]

permutations :: seq -> [seq]

permutations returns a list of all permutations of the argument.

> permutations "abc"
["abc","bac","cba","bca","cab","acb"]

tailEx :: seq -> seq

Unsafe

Get the tail of a sequence, throw an exception if the sequence is empty.

> tailEx [1,2,3]
[2,3]

initEx :: seq -> seq

Unsafe

Get the init of a sequence, throw an exception if the sequence is empty.

> initEx [1,2,3]
[1,2]

unsafeTail :: seq -> seq

Equivalent to tailEx.

unsafeInit :: seq -> seq

Equivalent to initEx.

index :: seq -> Index seq -> Maybe (Element seq)

Get the element of a sequence at a certain index, returns Nothing if that index does not exist.

> index (fromList [1,2,3] :: Vector Int) 1
Just 2
> index (fromList [1,2,3] :: Vector Int) 4
Nothing

indexEx :: seq -> Index seq -> Element seq

Unsafe

Get the element of a sequence at a certain index, throws an exception if the index does not exist.

unsafeIndex :: seq -> Index seq -> Element seq

Equivalent to indexEx.

intercalate :: seq -> [seq] -> seq

intercalate seq seqs inserts seq in between seqs and concatenates the result.

Since 0.9.3

splitWhen :: (Element seq -> Bool) -> seq -> [seq]

splitWhen splits a sequence into components delimited by separators, where the predicate returns True for a separator element. The resulting components do not contain the separators. Two adjacent separators result in an empty component in the output. The number of resulting components is greater by one than number of separators.

Since 0.9.3

Instances

IsSequence ByteString

IsSequence ByteString

IsSequence Text

IsSequence Text

IsSequence [a]

IsSequence (Seq a)

IsSequence (DList a)

IsSequence (Vector a)

Unbox a => IsSequence (Vector a)

Storable a => IsSequence (Vector a)

defaultFind :: MonoFoldable seq => (Element seq -> Bool) -> seq -> Maybe (Element seq)

Use Data.List's implementation of find.

defaultIntersperse :: IsSequence seq => Element seq -> seq -> seq

Use Data.List's implementation of intersperse.

defaultReverse :: IsSequence seq => seq -> seq

Use Data.List's implementation of reverse.

defaultSortBy :: IsSequence seq => (Element seq -> Element seq -> Ordering) -> seq -> seq

Use Data.List's implementation of sortBy.

defaultIntercalate :: IsSequence seq => seq -> [seq] -> seq

Default intercalate

defaultSplitWhen :: IsSequence seq => (Element seq -> Bool) -> seq -> [seq]

Use splitWhen from Data.List.Split

vectorSortBy :: Vector v e => (e -> e -> Ordering) -> v e -> v e

Sort a vector using an supplied element ordering function.

vectorSort :: (Vector v e, Ord e) => v e -> v e

Sort a vector.

defaultCons :: IsSequence seq => Element seq -> seq -> seq

Use Data.List's : to prepend an element to a sequence.

defaultSnoc :: IsSequence seq => seq -> Element seq -> seq

Use Data.List's ++ to append an element to a sequence.

tailDef :: IsSequence seq => seq -> seq

like Data.List.tail, but an input of mempty returns mempty

initDef :: IsSequence seq => seq -> seq

like Data.List.init, but an input of mempty returns mempty

class (MonoFoldableEq seq, IsSequence seq, Eq (Element seq)) => EqSequence seq where

A typeclass for sequences whose elements have the Eq typeclass

Minimal complete definition

Nothing

Methods

splitElem :: Element seq -> seq -> [seq]

splitElem splits a sequence into components delimited by separator element. It's equivalent to splitWhen with equality predicate:

splitElem sep === splitWhen (== sep)

Since 0.9.3

splitSeq :: seq -> seq -> [seq]

splitSeq splits a sequence into components delimited by separator subsequence. splitSeq is the right inverse of intercalate:

intercalate x . splitSeq x === id

splitElem can be considered a special case of splitSeq

splitSeq (singleton sep) === splitElem sep

splitSeq mempty is another special case: it splits just before each element, and in line with splitWhen rules, it has at least one output component:

> splitSeq "" ""
[""]
> splitSeq "" "a"
["", "a"]
> splitSeq "" "ab"
["", "a", "b"]

Since 0.9.3

stripPrefix :: seq -> seq -> Maybe seq

stripPrefix drops the given prefix from a sequence. It returns Nothing if the sequence did not start with the prefix given, or Just the sequence after the prefix, if it does.

> stripPrefix "foo" "foobar"
Just "foo"
> stripPrefix "abc" "foobar"
Nothing

stripSuffix :: seq -> seq -> Maybe seq

stripSuffix drops the given suffix from a sequence. It returns Nothing if the sequence did not end with the suffix given, or Just the sequence before the suffix, if it does.

> stripSuffix "bar" "foobar"
Just "foo"
> stripSuffix "abc" "foobar"
Nothing

isPrefixOf :: seq -> seq -> Bool

isPrefixOf takes two sequences and returns True if the first sequence is a prefix of the second.

isSuffixOf :: seq -> seq -> Bool

isSuffixOf takes two sequences and returns True if the first sequence is a suffix of the second.

isInfixOf :: seq -> seq -> Bool

isInfixOf takes two sequences and returns true if the first sequence is contained, wholly and intact, anywhere within the second.

group :: seq -> [seq]

Equivalent to groupBy (==)

groupAll :: seq -> [seq]

Similar to standard group, but operates on the whole collection, not just the consecutive items.

Equivalent to groupAllOn id

Instances

EqSequence ByteString

EqSequence ByteString

EqSequence Text

EqSequence Text

Eq a => EqSequence [a]

Eq a => EqSequence (Seq a)

Eq a => EqSequence (Vector a)

(Eq a, Unbox a) => EqSequence (Vector a)

(Eq a, Storable a) => EqSequence (Vector a)

elem :: EqSequence seq => Element seq -> seq -> Bool

Deprecated: use oelem

notElem :: EqSequence seq => Element seq -> seq -> Bool

Deprecated: use onotElem

defaultSplitOn :: EqSequence s => s -> s -> [s]

Use splitOn from Data.List.Split

class (EqSequence seq, MonoFoldableOrd seq) => OrdSequence seq where

A typeclass for sequences whose elements have the Ord typeclass

Minimal complete definition

Nothing

Methods

sort :: seq -> seq

Sort a ordered sequence.

> sort [4,3,1,2]
[1,2,3,4]

Instances

OrdSequence ByteString

OrdSequence ByteString

OrdSequence Text

OrdSequence Text

Ord a => OrdSequence [a]

Ord a => OrdSequence (Seq a)

Ord a => OrdSequence (Vector a)

(Ord a, Unbox a) => OrdSequence (Vector a)

(Ord a, Storable a) => OrdSequence (Vector a)

class (IsSequence t, IsString t, Element t ~ Char) => Textual t where

A typeclass for sequences whose elements are Chars.

Minimal complete definition

words, unwords, lines, unlines, toLower, toUpper, toCaseFold

Methods

words :: t -> [t]

Break up a textual sequence into a list of words, which were delimited by white space.

> words "abc  def ghi"
["abc","def","ghi"]

unwords :: [t] -> t

Join a list of textual sequences using seperating spaces.

> unwords ["abc","def","ghi"]
"abc def ghi"

lines :: t -> [t]

Break up a textual sequence at newline characters.

> lines "hello\nworld"
["hello","world"]

unlines :: [t] -> t

Join a list of textual sequences using newlines.

> unlines ["abc","def","ghi"]
"abc\ndef\nghi"

toLower :: t -> t

Convert a textual sequence to lower-case.

> toLower "HELLO WORLD"
"hello world"

toUpper :: t -> t

Convert a textual sequence to upper-case.

> toUpper "hello world"
"HELLO WORLD"

toCaseFold :: t -> t

Convert a textual sequence to folded-case.

Slightly different from toLower, see Data.Text.toCaseFold

breakWord :: t -> (t, t)

Split a textual sequence into two parts, split at the first space.

> breakWord "hello world"
("hello","world")

breakLine :: t -> (t, t)

Split a textual sequence into two parts, split at the newline.

> breakLine "abc\ndef"
("abc","def")

Instances

Textual Text

Textual Text

(~) * c Char => Textual [c]

catMaybes :: (IsSequence (f (Maybe t)), Functor f, Element (f (Maybe t)) ~ Maybe t) => f (Maybe t) -> f t

Takes all of the Just values from a sequence of Maybe ts and concatenates them into an unboxed sequence of ts.

Since 0.6.2

sortOn :: (Ord o, SemiSequence seq) => (Element seq -> o) -> seq -> seq

Same as sortBy . comparing.

Since 0.7.0