Mutable vector: clear reference at given index

Question

I understand that the vector provides a mutable interface which includes the clear function, clearing references to all the objects stored in the vector. I can't find a similar function that would clear the reference stored at index n in the vector. Is there any way to achieve such a thing, and if not, why?

NB: The function would look something like this:

clearAtIndex :: MVector (PrimState m) a -> Int -> m ()

Answer 1

There's nothing like that in the package itself, but one can use the same implementation as clear :

clearAtIndex :: MVector (PrimState m) a -> Int -> m ()
clearAtIndex v n = write v n uninitialised

uninitialised :: a
uninitialised = error "clearAtIndex: uninitialised element"

clear basically works the same, but uses set v uninitialised in order to use possible optimizations.