Paul Sujkov wrote:
I played a bit with the enumerator package, and I'm quite stuck with the question how to duplex data to two (or more) consumers
Many packages have the combinator named enumPair (or something like that). Here is one example http://okmij.org/ftp/ftp/Streams.html#1enum2iter The combinator is quite useful for logging, for dumping the contents of the stream as it is being processed.
actually I need to pipeline output of one consumer to another (outputting text after making some internal representation - with Show instance - with the parseData).
You need enumeratees, which convert one stream into another. There are many examples of those: e.g., converting a stream of bytes into a stream of lines, or a stream of compressed/encoded data into the plaintext stream. You enumerator package probably has them. The Stream.html page also describes many examples of enumeratees.