sorted-list-0.1.2.0: Type-enforced sorted lists and related functions.

Data.SortedList

Description

This module defines a type for sorted lists, together with several functions to create and use values of that type. Many operations are optimized to take advantage of the list being sorted.

Synopsis

Type

data SortedList a Source

Type of sorted lists. Any (non-bottom) value of this type is a sorted list.

Instances

 Foldable SortedList Show a => Show (SortedList a) Ord a => Monoid (SortedList a)

List conversions

toSortedList :: Ord a => [a] -> SortedList a Source

Create a `SortedList` by sorting a regular list.

fromSortedList :: SortedList a -> [a] Source

Create a list from a `SortedList`. The returned list is guaranteed to be sorted.

Construction

singleton :: a -> SortedList a Source

O(1). Create a sorted list with only one element.

repeat :: a -> SortedList a Source

An infinite list with all its elements equal to the given argument.

replicate :: Int -> a -> SortedList a Source

Replicate a given number of times a single element.

iterate :: Ord a => (a -> a) -> a -> SortedList a Source

Create a sorted list by repeatedly applying the same function to an element, until the image by that function is stricly less than its argument. In other words:

`iterate f x = [x, f x, f (f x), ... ]`

With the list ending whenever `f (f (... (f (f x)) ...)) < f (... (f (f x)) ...)`. If this never happens, the list will be infinite.

Deconstruction

uncons :: SortedList a -> Maybe (a, SortedList a) Source

Decompose a sorted list into its minimal element and the rest. If the list is empty, it returns `Nothing`.

Inserting

insert :: Ord a => a -> SortedList a -> SortedList a Source

O(n). Insert a new element in a sorted list.

Sublists

take :: Int -> SortedList a -> SortedList a Source

Extract the prefix with the given length from a sorted list.

drop :: Int -> SortedList a -> SortedList a Source

Drop the given number of elements from a sorted list, starting from the smallest and following ascending order.

splitAt :: Int -> SortedList a -> (SortedList a, SortedList a) Source

Split a sorted list in two sublists, with the first one having length equal to the given argument, except when the length of the list is less than that.

filter :: (a -> Bool) -> SortedList a -> SortedList a Source

O(n). Extract the elements of a list that satisfy the predicate.

Queries

null :: SortedList a -> Bool Source

Check if a sorted list is empty.

elemOrd :: Ord a => a -> SortedList a -> Bool Source

O(n). An efficient implementation of `elem`, using the `Ord` instance of the elements in a sorted list. It only traverses the whole list if the requested element is greater than all the elements in the sorted list.

Others

map :: Ord b => (a -> b) -> SortedList a -> SortedList b Source

Map a function over all the elements of a sorted list. Note that `map` will hang if the argument is an infinite list.

Even though `SortedList` can't be made an instance of `Functor`, `map` does hold the `Functor` laws. The problem to write the the instance is the `Ord` instance requirement on the type of the elements of the result list. Therefore, while `SortedList` is not a functor type in general, it is when restricted to elements of orderable types.

nub :: Eq a => SortedList a -> SortedList a Source

O(n). Remove duplicate elements from a sorted list.