| Safe Haskell | None |
|---|---|
| Language | Haskell2010 |
Mikan.Utils.ListInf
Description
Infinite lists (streams).
Wrapper for Data.List.Infinite from the infinite-list package
that generalizes some type signatures, using Integral for indexing,
and adds some missing functions.
Import this module as follows:
import Mikan.Utils.ListInf (ListInf, pattern (:<)) import Mikan.Utils.ListInf qualified as ListInf
Motivation: lists constructed by repeat, iterate, cycle etc.
are infinite, so the nil case can never arise when consuming them,
e.g. in a take or zipWith.
Constructing them as properly infinite lists (ListInf) should thus
lead to slightly more efficient code, eliminating impossible cases.
Synopsis
- type ListInf = Infinite
- append :: [a] -> ListInf a -> ListInf a
- pad :: [a] -> a -> ListInf a
- upFrom :: Enum n => n -> ListInf n
- updateAt :: Integral n => n -> (a -> a) -> ListInf a -> ListInf a
- (!!) :: Integral n => ListInf a -> n -> a
- take :: Integral n => n -> ListInf a -> [a]
- drop :: Integral n => n -> ListInf a -> ListInf a
- splitAt :: Integral n => n -> ListInf a -> ([a], ListInf a)
- cycle :: NonEmpty a -> Infinite a
- head :: Infinite a -> a
- iterate :: (a -> a) -> a -> Infinite a
- prependList :: [a] -> Infinite a -> Infinite a
- repeat :: a -> Infinite a
- tail :: Infinite a -> Infinite a
- zip :: Infinite a -> Infinite b -> Infinite (a, b)
- zipWith :: (a -> b -> c) -> Infinite a -> Infinite b -> Infinite c
- pattern (:<) :: a -> Infinite a -> Infinite a
Documentation
Construction
append :: [a] -> ListInf a -> ListInf a Source #
There is only one meaningful way to concatenate a finite and an infinite list,
justifying the name append = prependList.
Selection
updateAt :: Integral n => n -> (a -> a) -> ListInf a -> ListInf a Source #
\(\Theta(n)\). Update the nth element of an infinite list.
Precondition: the index n is >= 0.
Generalized versions of functions from infinite-list
take :: Integral n => n -> ListInf a -> [a] Source #
\(\Theta(n)\). Take n elements from an infinite list.
drop :: Integral n => n -> ListInf a -> ListInf a Source #
\(\Theta(n)\). Drop n elements from an infinite list.
splitAt :: Integral n => n -> ListInf a -> ([a], ListInf a) Source #
\(\Theta(n)\). Split an infinite list at the nth element.
Laws
splitAt n xs = (take n xs, drop n xs)
Re-exports
cycle :: NonEmpty a -> Infinite a #
Repeat a non-empty list ad infinitum.
If you were looking for something like fromList :: [a] -> Infinite a,
look no further.
It would be less annoying to take [a] instead of NonEmpty a,
but we strive to avoid partial functions.
prependList :: [a] -> Infinite a -> Infinite a #
Prepend a list to an infinite list.