Agda-2.3.0: A dependently typed functional programming language and proof assistant



Utitlity functions on lists.



mhead :: [a] -> Maybe aSource

Head function (safe).

isSublistOf :: Eq a => [a] -> [a] -> BoolSource

Sublist relation.

type Prefix a = [a]Source

type Suffix a = [a]Source

maybePrefixMatch :: Eq a => Prefix a -> [a] -> Maybe (Suffix a)Source

Check if a list has a given prefix. If so, return the list minus the prefix.

wordsBy :: (a -> Bool) -> [a] -> [[a]]Source

Split a list into sublists. Generalisation of the prelude function words.

 words xs == wordsBy isSpace xs

chop :: Int -> [a] -> [[a]]Source

Chop up a list in chunks of a given length.

holes :: [a] -> [(a, [a])]Source

All ways of removing one element from a list.

distinct :: Eq a => [a] -> BoolSource

Check whether all elements in a list are distinct from each other. Assumes that the Eq instance stands for an equivalence relation.

fastDistinct :: Ord a => [a] -> BoolSource

An optimised version of distinct.

Precondition: The list's length must fit in an Int.

allEqual :: Eq a => [a] -> BoolSource

Checks if all the elements in the list are equal. Assumes that the Eq instance stands for an equivalence relation.

groupBy' :: (a -> a -> Bool) -> [a] -> [[a]]Source

A variant of groupBy which applies the predicate to consecutive pairs.

groupOn :: Ord b => (a -> b) -> [a] -> [[a]]Source

groupOn f = groupBy ((==) `on` f) . sortBy (compare `on` f).

extractNthElement' :: Integral i => i -> [a] -> ([a], a, [a])Source

extractNthElement n xs gives the n-th element in xs (counting from 0), plus the remaining elements (preserving order).

extractNthElement :: Integral i => i -> [a] -> (a, [a])Source

genericElemIndex :: (Eq a, Integral i) => a -> [a] -> Maybe iSource

zipWith' :: (a -> b -> c) -> [a] -> [b] -> [c]Source

Requires both lists to have the same length.

uniqBy :: Ord b => (a -> b) -> [a] -> [a]Source

Efficient version of nub that sorts the list first. The tag function is assumed to be cheap. If it isn't pair up the elements with their tags and call uniqBy fst (or snd).