map is:exact -package:text -package:Cabal-syntax -package:basement -package:bytestring -package:charset -package:imports -package:incipit-base -package:hedgehog -package:base -package:case-insensitive -package:monoidal-containers package:pipes

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

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