CODEWITHSUNDEEP
haskellvectorfunctional-programming
Nicolas Mattia
Nicolas Mattia

Reputation: 1309

Mutable vector: clear reference at given index

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 ()

Upvotes: 0

Views: 55

Answers (1)

Zeta
Zeta

Reputation: 105965

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.

Upvotes: 4

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