Joachim Breitner
I’m consdering to change some performance critical code from Vector to MVector, hopefully avoiding a lot of copying and garbage collecting. But it seems that the Data.Vector.Mutable interface at http://hackage.haskell.org/packages/archive/vector/0.9/doc/html/Data-Vector-... is quite limited; e.g. I am missing simple functions having type modifyM :: PrimMonad m => (a -> m a) -> MVector (PrimState m) a -> m () that would do something with each element in the vector.
Is this an indication that such use is actually not desired, or is it just the case that nobody has developed that yet?
In general you should try to work with immutable vectors as much as possible. Done properly you shouldn't lose much performance that way. However, sometimes an operation is just much easier to express and faster with the MVector interface. In these cases you can escape to the mutable interface using 'create', 'modify', 'thaw' and 'freeze'. Don't forget that you lose fusion that way, though. In other words: Don't use MVector exclusively. Use it only when you really need it. Greets, Ertugrul -- nightmare = unsafePerformIO (getWrongWife >>= sex) http://ertes.de/