[Haskell-cafe] Replacing stdin from within Haskell

Hi Anyone out there got an elegant solution to being able to fork a haskell thread and replace its 'stdin' ? Why do I want this - well I'm using the pcap library and I want to uncompress data to feed into 'openOffile' (which will take "-" to designate read from stdin). Yes I can create a separate command and use the stuff in System.Process or uncompress it into a temporary file - but that all seems in-elegant. Suggestions? Cheers Neil