With observe in the new hugs beta we have an interesting new toy to play with. I tried observing the state (current character, line and column) of an (inefficient) monadic expression parser to see the amount of backtracking, but I immediately ran into the limit on number of observation tags (400). I guess I used observe in a way it was not inteded for ... observe (show (c,line,col)) c ... producing lots of tag, each with a few (identical) observations, but nevertheless it would be nice to have a simpler way of changing the maximum number of tags than to recompile hugs. (Or at least have a larger default for big hugs.) (For the record, 4000 was not enough either for this example.) When debugging, or performance evaluating using HugsHood it would also be nice to have a possibility of storing something else than just a list of observed values. For the parser example (and in many other cases), just incrementing a tag-specific counter at each evaluation of observe (or a similar extended function) would be very useful. /Patrik Jansson