[Haskell-cafe] mapM for vectors
schlepptop at henning-thielemann.de
Fri Apr 9 17:06:19 EDT 2010
Don Stewart schrieb:
>> I found that there is no monadic map for vector. It's possible to define to
>> define such map using conversion to list, but I suppose it's not efficient. I
>> didn't make any measurements.
>>> mapM' :: Monad m => (a -> m b) -> V.Vector a -> m (V.Vector b)
>>> mapM' f = return . V.fromList <=< mapM f . V.toList
>> Any suggestions about implementation of such function?
>> Specifically I want to use Random monad.
> There's a tutorial here on usving vectors,
> mapM is available via Fusion.Stream.Monadic.mapM
But can it be efficient? It must handle cases like m =  and thus
creation of the (V.Vector b) result means a lot of copying, right?
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