Hello cafe, I've hit a bit of a monadic snag here... I'm scanning a big file, building a table of statistics. I end up with something like IO (IntMap (IOUArray Int Double)) Once I've read in the whole file and built my statistics, I don't need any more updates, so I'd like to do something like IntMap (IOUArray Int Double) -> IO (IntMap (UArray Int Double)), using unsafeFreeze. I'm getting stuck here, since the IntMap library is not so monad-friendly. I could rebuild the whole thing using sequence and lists, but the table is pretty big (4.5 million keys on a first run), so I'd prefer to avoid that. Any ideas? BTW, I probably "should" be using ST for this, but I hit the usual "type s escapes" irritation and gave up. If that would work more easily, that would be fine with me too. Thanks! Chad Scherrer