map is:exact -package:text -package:amazonka-core -package:case-insensitive -package:dlist -package:containers -package:invertible -package:incipit-base -package:dense-linear-algebra -package:Cabal-syntax -package:insert-ordered-containers -package:monoidal-containers package:pipes

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

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