map -package:base-prelude -package:base-compat -package:case-insensitive -package:bytestring -package:blaze-html -package:charset -package:imports -package:basement -package:dense-linear-algebra -package:Cabal-syntax -package:hedgehog -package:dlist package:pipes is:exact

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

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