[Haskell-cafe] mapping unfreeze over an IntMap of IOUArrays
chad.scherrer at pnl.gov
Tue Nov 11 14:23:09 EST 2008
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
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
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
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.
More information about the Haskell-Cafe