map -package:containers -package:imports -package:dense-linear-algebra -package:case-insensitive -package:conduit -package:basement -package:filepath -package:blaze-html -package:aeson -package:hedgehog -package:charset -package:os-string -package:regex-tdfa -package:pipes -package:unordered-containers -package:psqueues -package:base-prelude -package:bytestring 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