map -package:containers -package:insert-ordered-containers -package:dense-linear-algebra -package:invertible -package:monoidal-containers -package:Cabal-syntax -package:foldl -package:case-insensitive -package:bytestring -package:aeson is:exact package:pipes

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

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