map -package:base -is:exact -is:exact -package:unordered-containers -package:bytestring -package:ghc is:exact -package:case-insensitive -package:vector -package:regex-tdfa -package:containers package:streaming

Standard map on the elements of a stream.
>>> S.stdoutLn $ S.map reverse $ each (words "alpha beta")
ahpla
ateb