map -package:Cabal -package:base -package:text -package:dlist -package:aeson -package:bytestring -package:vector is:exact package:io-streams

map :: (a -> b) -> InputStream a -> IO (InputStream b)
io-streams System.IO.Streams.Combinators
Maps a pure function over an InputStream. map f s passes all output from s through the function f. Satisfies the following laws: 
Streams.map (g . f) === Streams.map f >=> Streams.map g
Streams.map id === Streams.makeInputStream . Streams.read