map -package:containers -package:insert-ordered-containers -package:basement -is:exact -package:base-prelude -package:bytestring -is:exact -package:dlist -package:Cabal-syntax -package:ghc -package:conduit -package:charset -package:regex-tdfa -package:psqueues -package:vector -package:text 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