Hi John, thanks for responding. As I said I've been using Parsec quite a lot, but wonder if there is a different approach possible/feasible to parsing. Parsec (2x) isn't an "online" parser, ie, it doesn't produce a result before the whole parse is completed. There is AFAIK one alternative, the uulib, but at first glance it seemed very elaborate, so I wonder if Oleg's Iteratee offers something simpler. I am not in particular looking for some sort of parsec-iteratee-hybrid, I'd be quite happy with something entirely based on Iteratee. In the Iteratee package there are 2 sample parsers, one for TIFF and one for WAVE files. I wish I could say that the accompanying documentation is sufficient for me to get the idea, alas it's not. Günther