On 02/04/2010, at 12:16, Don Stewart wrote:
Chad.Scherrer:
Hi,
I'd like to be able to do replicateM, but over a vector instead of a list. Right now I'm doing this:
The operation you are looking for is called newWith. It probably should be called replicate.
Roman? Can we generate frozen arrays for monadic generators, and still fuse in the current New/Mutable/MStream architecture?
For monadic stuff, fusion happens on things of type New. For instance, you could write this (I'm omitting the class contexts and Data.Vector prefixes): replicate :: Int -> a -> New a replicate n x = Generic.New.unstream (Fusion.Stream.replicate n x) and then either Mutable.run (replicate n x) to get a mutable vector or new (replicate n x) to get an immutable one. You could also chain operations on New, including monadic ones: v <- Mutable.run $ Generic.New.transform (Fusion.Stream.Monadic.mapM f) $ replicate n x and this ought to fuse. Note that the New stuff is quite rough and only really intended for internal use at the moment. I wanted to get the "normal" APIs working properly first. Roman