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Seq.cache
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I like the possibilities that this function potentially has. But what I would like to know is if I do the following

let xs = seq{for i in 1 .. 200 do for k in 400 .. 600 do yield (i,k)};;

let xs' = Seq.cache xs
let xs'' = Seq.cache xs'

will the second invocation of Seq.cache lead to the Seq.cache function simply returning since xs' is already a CachedSeq. or will it treat the CachedSeq, xs', as a Seq?

.

So I took a look at the code included in the distrib and assuming I am not misinterpreting the code. Then Seq.Cache would treat a CachedSeq as a seq and at the very least new up another CachedSeq.

My main motiviation for asking this question stems from the lack of a unzip function in the Seq module. Fortunately it is trivial to implement but to keep with the main idea of a stream, I thought it was important to make sure that unzip works only on CachedSeq's which prevent reevaluating the lazy stream when either of streams in the returned pair is consumed. With that said I wonder why the decision was made not to include any unzip functions in the Seq module.

By on 10/11/2008 6:44 AM ()

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