Portability	portable
Stability	provisional
Maintainer	John Goerzen <jgoerzen@complete.org>

Data.ListLike.Base

Description

Generic operations over list-like structures

Written by John Goerzen, jgoerzen@complete.org

Synopsis

Documentation

class (FoldableLL full item, Monoid full) => ListLike full item | full -> item whereSource

The class implementing list-like functions.

It is worth noting that types such as Data.Map.Map can be instances of ListLike. Due to their specific ways of operating, they may not behave in the expected way in some cases. For instance, cons may not increase the size of a map if the key you have given is already in the map; it will just replace the value already there.

Implementators must define at least:

singleton
head
tail
null or genericLength

Methods

empty :: fullSource

The empty list

singleton :: item -> fullSource

Creates a single-element list out of an element

cons :: item -> full -> fullSource

Like (:) for lists: adds an element to the beginning of a list

snoc :: full -> item -> fullSource

Adds an element to the *end* of a ListLike.

append :: full -> full -> fullSource

Combines two lists. Like (++).

head :: full -> itemSource

Extracts the first element of a ListLike.

last :: full -> itemSource

Extracts the last element of a ListLike.

tail :: full -> fullSource

Gives all elements after the head.

init :: full -> fullSource

All elements of the list except the last one. See also inits.

null :: full -> Bool Source

Tests whether the list is empty.

length :: full -> Int Source

Length of the list. See also genericLength.

map :: ListLike full' item' => (item -> item') -> full -> full'Source

Apply a function to each element, returning any other valid ListLike. rigidMap will always be at least as fast, if not faster, than this function and is recommended if it will work for your purposes. See also mapM.

rigidMap :: (item -> item) -> full -> fullSource

Like map, but without the possibility of changing the type of the item. This can have performance benefits for things such as ByteStrings, since it will let the ByteString use its native low-level map implementation.

reverse :: full -> fullSource

Reverse the elements in a list.

intersperse :: item -> full -> fullSource

Add an item between each element in the structure

concat :: (ListLike full' full, Monoid full) => full' -> fullSource

Flatten the structure.

concatMap :: ListLike full' item' => (item -> full') -> full -> full'Source

Map a function over the items and concatenate the results. See also rigidConcatMap.

rigidConcatMap :: (item -> full) -> full -> fullSource

Like concatMap, but without the possibility of changing the type of the item. This can have performance benefits for some things such as ByteString.

any :: (item -> Bool) -> full -> Bool Source

True if any items satisfy the function

all :: (item -> Bool) -> full -> Bool Source

True if all items satisfy the function

maximum :: Ord item => full -> itemSource

The maximum value of the list

minimum :: Ord item => full -> itemSource

The minimum value of the list

replicate :: Int -> item -> fullSource

Generate a structure with the specified length with every element set to the item passed in. See also genericReplicate

take :: Int -> full -> fullSource

Takes the first n elements of the list. See also genericTake.

drop :: Int -> full -> fullSource

Drops the first n elements of the list. See also genericDrop

splitAt :: Int -> full -> (full, full)Source

Equivalent to (take n xs, drop n xs). See also genericSplitAt.

takeWhile :: (item -> Bool) -> full -> fullSource

Returns all elements at start of list that satisfy the function.

dropWhile :: (item -> Bool) -> full -> fullSource

Drops all elements form the start of the list that satisfy the function.

span :: (item -> Bool) -> full -> (full, full)Source

The equivalent of (takeWhile f xs, dropWhile f xs)

break :: (item -> Bool) -> full -> (full, full)Source

The equivalent of span (not . f)

group :: (ListLike full' full, Eq item) => full -> full'Source

Split a list into sublists, each which contains equal arguments. For order-preserving types, concatenating these sublists will produce the original list. See also groupBy.

inits :: ListLike full' full => full -> full'Source

All initial segments of the list, shortest first

tails :: ListLike full' full => full -> full'Source

All final segnemts, longest first

isPrefixOf :: Eq item => full -> full -> Bool Source

True when the first list is at the beginning of the second.

isSuffixOf :: Eq item => full -> full -> Bool Source

True when the first list is at the beginning of the second.

isInfixOf :: Eq item => full -> full -> Bool Source

True when the first list is wholly containted within the second

elem :: Eq item => item -> full -> Bool Source

True if the item occurs in the list

notElem :: Eq item => item -> full -> Bool Source

True if the item does not occur in the list

find :: (item -> Bool) -> full -> Maybe itemSource

Take a function and return the first matching element, or Nothing if there is no such element.

filter :: (item -> Bool) -> full -> fullSource

Returns only the elements that satisfy the function.

partition :: (item -> Bool) -> full -> (full, full)Source

Returns the lists that do and do not satisfy the function. Same as (filter p xs, filter (not . p) xs)

index :: full -> Int -> itemSource

The element at 0-based index i. Raises an exception if i is out of bounds. Like (!!) for lists.

elemIndex :: Eq item => item -> full -> Maybe Int Source

Returns the index of the element, if it exists.

elemIndices :: (Eq item, ListLike result Int) => item -> full -> resultSource

Returns the indices of the matching elements. See also findIndices

findIndex :: (item -> Bool) -> full -> Maybe Int Source

Take a function and return the index of the first matching element, or Nothing if no element matches

findIndices :: ListLike result Int => (item -> Bool) -> full -> resultSource

Returns the indices of all elements satisfying the function

sequence :: (Monad m, ListLike fullinp (m item)) => fullinp -> m fullSource

Evaluate each action in the sequence and collect the results

mapM :: (Monad m, ListLike full' item') => (item -> m item') -> full -> m full'Source

A map in monad space. Same as sequence . map

See also rigidMapM

rigidMapM :: Monad m => (item -> m item) -> full -> m fullSource

Like mapM, but without the possibility of changing the type of the item. This can have performance benefits with some types.

mapM_ :: Monad m => (item -> m b) -> full -> m ()Source

A map in monad space, discarding results. Same as sequence_ . map

nub :: Eq item => full -> fullSource

Removes duplicate elements from the list. See also nubBy

delete :: Eq item => item -> full -> fullSource

Removes the first instance of the element from the list. See also deleteBy

deleteFirsts :: Eq item => full -> full -> fullSource

List difference. Removes from the first list the first instance of each element of the second list. See '(\)' and deleteFirstsBy

union :: Eq item => full -> full -> fullSource

List union: the set of elements that occur in either list. Duplicate elements in the first list will remain duplicate. See also unionBy.

intersect :: Eq item => full -> full -> fullSource

List intersection: the set of elements that occur in both lists. See also intersectBy

sort :: Ord item => full -> fullSource

Sorts the list. On data types that do not preserve ordering, or enforce their own ordering, the result may not be what you expect. See also sortBy.

insert :: Ord item => item -> full -> fullSource

Inserts the element at the last place where it is still less than or equal to the next element. On data types that do not preserve ordering, or enforce their own ordering, the result may not be what you expect. On types such as maps, this may result in changing an existing item. See also insertBy.

toList :: full -> [item]Source

Converts the structure to a list. This is logically equivolent to fromListLike, but may have a more optimized implementation.

fromList :: [item] -> fullSource

Generates the structure from a list.

fromListLike :: ListLike full' item => full -> full'Source

Converts one ListLike to another. See also toList. Default implementation is fromListLike = map id

nubBy :: (item -> item -> Bool) -> full -> fullSource

Generic version of nub

deleteBy :: (item -> item -> Bool) -> item -> full -> fullSource

Generic version of deleteBy

deleteFirstsBy :: (item -> item -> Bool) -> full -> full -> fullSource

Generic version of deleteFirsts

unionBy :: (item -> item -> Bool) -> full -> full -> fullSource

Generic version of union

intersectBy :: (item -> item -> Bool) -> full -> full -> fullSource

Generic version of intersect

groupBy :: (ListLike full' full, Eq item) => (item -> item -> Bool) -> full -> full'Source

Generic version of group.

sortBy :: (item -> item -> Ordering) -> full -> fullSource

Sort function taking a custom comparison function

insertBy :: (item -> item -> Ordering) -> item -> full -> fullSource

Like insert, but with a custom comparison function

genericLength :: Num a => full -> aSource

Length of the list

genericTake :: Integral a => a -> full -> fullSource

Generic version of take

genericDrop :: Integral a => a -> full -> fullSource

Generic version of drop

genericSplitAt :: Integral a => a -> full -> (full, full)Source

Generic version of splitAt

genericReplicate :: Integral a => a -> item -> fullSource

Generic version of replicate

Instances

ListLike ByteString Word8
ListLike ByteString Word8
ListLike CharStringLazy Char
ListLike CharString Char
ListLike [a] a
ListLike (Seq a) a
(Integral i, Ix i) => ListLike (Array i e) e

class ListLike full item => InfiniteListLike full item | full -> item whereSource

An extension to ListLike for those data types that are capable of dealing with infinite lists. Some ListLike functions are capable of working with finite or infinite lists. The functions here require infinite list capability in order to work at all.

Methods

iterate :: (item -> item) -> item -> fullSource

An infinite list of repeated calls of the function to args

repeat :: item -> fullSource

An infinite list where each element is the same

cycle :: full -> fullSource

Converts a finite list into a circular one

Instances

InfiniteListLike [a] a

zip :: (ListLike full item, ListLike fullb itemb, ListLike result (item, itemb)) => full -> fullb -> resultSource

Takes two lists and returns a list of corresponding pairs.

zipWith :: (ListLike full item, ListLike fullb itemb, ListLike result resultitem) => (item -> itemb -> resultitem) -> full -> fullb -> resultSource

Takes two lists and combines them with a custom combining function

sequence_ :: (Monad m, ListLike mfull (m item)) => mfull -> m ()Source

Evaluate each action, ignoring the results