**Packages**- fgl
- quickcheck
- base

The sort function implements a stable sorting algorithm. It is a special case of sortBy, which allows the programmer to supply their own comparison function.

The insert function takes an element and a list and inserts the element into the list at the last position or equal to the next element. In particular, if the list is sorted before the call, the result will also be sorted. It is a special case of insertBy, which allows the programmer to supply their own comparison function.

cycle ties a finite list into a circular one, or equivalently, the infinite repetition of the original list. It is the identity on infinite lists.

Return all the elements of a list except the last one. The list must be non-empty.

reverse xs returns the elements of xs in reverse order. xs must be finite.

Extract the elements after the head of a list, which must be non-empty.

maximum returns the maximum value from a list, which must be non-empty, finite, and of an ordered type. It is a special case of maximumBy, which allows the programmer to supply their own comparison function.

minimum returns the minimum value from a list, which must be non-empty, finite, and of an ordered type. It is a special case of minimumBy, which allows the programmer to supply their own comparison function.

A list producer that can be fused with foldr. This function is merely
> augment g xs = g (:) xs
but GHC's simplifier will transform an expression of the form foldr k z (augment g xs), which may arise after inlining, to g k (foldr k z xs), which avoids producing an intermediate list.

The sortWith function sorts a list of elements using the user supplied function to project something out of each element

scanl1 is a variant of scanl that has no starting value argument:
> scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]

The nubBy function behaves just like nub, except it uses a user-supplied equality predicate instead of the overloaded == function.

dropWhile p xs returns the suffix remaining after takeWhile p xs:
> dropWhile (< 3) [1,2,3,4,5,1,2,3] == [3,4,5,1,2,3]
> dropWhile (< 9) [1,2,3] == []
> dropWhile (< 0) [1,2,3] == [1,2,3]

filter, applied to a predicate and a list, returns the list of those elements that satisfy the predicate; i.e.,
> filter p xs = [ x | x <- xs, p x]

takeWhile, applied to a predicate p and a list xs, returns the longest prefix (possibly empty) of xs of elements that satisfy p:
> takeWhile (< 3) [1,2,3,4,1,2,3,4] == [1,2]
> takeWhile (< 9) [1,2,3] == [1,2,3]
> takeWhile (< 0) [1,2,3] == []

The genericDrop function is an overloaded version of drop, which accepts any Integral value as the number of elements to drop.

The genericTake function is an overloaded version of take, which accepts any Integral value as the number of elements to take.

The intersperse function takes an element and a list and `intersperses' that element between the elements of the list. For example,
> intersperse ',' "abcde" == "a,b,c,d,e"