map -package:containers -package:basement -package:conduit -is:exact -package:monoidal-containers -package:base -package:base-prelude -package:ghc -package:os-string -package:psqueues -package:bytestring -package:regex-tdfa -package:case-insensitive -package:filepath -package:amazonka-core -package:vector -package:base-compat-batteries 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