map -package:containers -package:ghc -is:exact -package:bytestring is:exact -package:basement -package:imports -package:foldl -package:hedgehog -package:conduit package:dlist

map f xs is the DList obtained by applying f to each element of xs. <math>(length (toList xs)). map obeys the law:
toList (map f xs) = map f (toList xs)
map f xs is the DNonEmpty obtained by applying f to each element of xs. <math>(length (toNonEmpty xs)). map obeys the law:
toNonEmpty (map f xs) = map f (toNonEmpty xs)