map -package:containers is:exact -package:conduit -package:charset -package:monoidal-containers -package:psqueues -package:filepath -package:foldl -package:bytestring -package:basement package:incipit-base

map f xs is the list obtained by applying f to each element of xs, i.e.,
map f [x1, x2, ..., xn] == [f x1, f x2, ..., f xn]
map f [x1, x2, ...] == [f x1, f x2, ...]
>>> map (+1) [1, 2, 3]
[2,3,4]