map -package:base -is:exact -is:exact -package:unordered-containers -package:case-insensitive -package:bytestring -package:blaze-html -package:hedgehog -package:pipes is:exact -package:vector package:streaming

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