map -package:dense-linear-algebra -is:exact -package:blaze-html -package:basement -is:exact -package:invertible is:exact -package:amazonka-core -package:incipit-base -package:containers -package:aeson -package:bytestring -package:monoidal-containers -package:charset -package:integration package:pipes

Apply a function to all values flowing downstream
map id = cat

map (g . f) = map f >-> map g