map -package:containers -package:basement -package:conduit -is:exact -is:exact -package:foldl -package:amazonka-core -package:Cabal-syntax -package:incipit-base -package:ghc -package:base-compat-batteries package:pipes is:exact

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

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