Data.List.Compat

Documentation

dropWhileEnd :: (a -> Bool) -> [a] -> [a]

The dropWhileEnd function drops the largest suffix of a list in which the given predicate holds for all elements. For example:

dropWhileEnd isSpace "foo\n" == "foo"
dropWhileEnd isSpace "foo bar" == "foo bar"
dropWhileEnd isSpace ("foo\n" ++ undefined) == "foo" ++ undefined

Since: 4.5.0.0

isSubsequenceOf :: Eq a => [a] -> [a] -> Bool

The isSubsequenceOf function takes two lists and returns True if the first list is a subsequence of the second list.

isSubsequenceOf x y is equivalent to elem x (subsequences y).

Since: 4.8.0.0

Examples

>>> isSubsequenceOf "GHC" "The Glorious Haskell Compiler"
True
>>> isSubsequenceOf ['a','d'..'z'] ['a'..'z']
True
>>> isSubsequenceOf [1..10] [10,9..0]
False

sortOn :: Ord b => (a -> b) -> [a] -> [a]

Sort a list by comparing the results of a key function applied to each element. sortOn f is equivalent to sortBy . comparing f, but has the performance advantage of only evaluating f once for each element in the input list. This is called the decorate-sort-undecorate paradigm, or Schwartzian transform.

Since: 4.8.0.0

uncons :: [a] -> Maybe (a, [a])

Decompose a list into its head and tail. If the list is empty, returns Nothing. If the list is non-empty, returns Just (x, xs), where x is the head of the list and xs its tail.

Since: 4.8.0.0