map -package:containers -package:aeson -package:incipit-base -package:charset -package:basement -package:monoidal-containers -package:ghc is:exact -package:dense-linear-algebra -package:invertible -package:base -package:base-prelude -package:base-compat -package:os-string -package:regex-tdfa -package:hedgehog -package:integration package:pipes

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

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