break package:hedgehog

break, applied to a predicate p and a list xs, returns a tuple where first element is longest prefix (possibly empty) of xs of elements that do not satisfy p and second element is the remainder of the list:
>>> break (> 3) [1,2,3,4,1,2,3,4]
([1,2,3],[4,1,2,3,4])

>>> break (< 9) [1,2,3]
([],[1,2,3])

>>> break (> 9) [1,2,3]
([1,2,3],[])
break p is equivalent to span (not . p).