:: (a -> Bool) -> [a] -> [a] package:utility-ht

Take all elements until one matches. The matching element is returned, too. This is the key difference to takeWhile (not . p). It holds:

forAllPredicates $ \p xs -> takeUntil p xs == fst (breakAfter p xs)

Deprecated: Use dropWhile from Data.List.Reverse.StrictElement or Data.List.Reverse.StrictSpine instead

Deprecated: Use takeWhile from Data.List.Reverse.StrictElement or Data.List.Reverse.StrictSpine instead

Remove the longest suffix of elements satisfying p. In contrast to reverse . dropWhile p . reverse this works for infinite lists, too.

forAllPredicates $ \p xs -> Rev.dropWhile p xs == reverse (List.dropWhile p (reverse xs))

\x xs pad -> defined $ Match.take (pad::[()]) $ Rev.dropWhile ((x::Char)/=) $ cycle $ x:xs

Alternative version of reverse . takeWhile p . reverse.

forAllPredicates $ \p xs -> Rev.takeWhile p xs == reverse (List.takeWhile p (reverse xs))

forAllPredicates $ \p xs -> Rev.dropWhile p xs == reverse (List.dropWhile p (reverse xs))

\x xs pad -> defined $ length $ Rev.dropWhile ((x::Char)/=) $ Match.replicate (pad::[()]) undefined ++ x:xs

forAllPredicates $ \p xs -> Rev.takeWhile p xs == reverse (List.takeWhile p (reverse xs))

\x xs pad -> defined $ Rev.takeWhile ((x::Char)/=) $ Match.replicate (pad::[()]) undefined ++ x:xs