map -package:conduit -is:exact -package:basement -package:aeson -package:charset -package:base-compat-batteries -is:exact -package:foldl -package:ghc -package:incipit-base -package:monoidal-containers -is:exact is:exact package:pipes

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

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