map -package:containers -package:basement -package:psqueues -package:Cabal-syntax -package:invertible -package:dense-linear-algebra -package:conduit -package:os-string -package:regex-tdfa -package:dlist -package:text -package:filepath -package:vector -is:exact -package:charset package:vector-stream

Map a function over a Stream
Map a monadic function over a Stream
Execute a monadic action for each element of the Stream
Apply monadic function to each element and drop all Nothings