[Haskell-cafe] [IO Int] -> IO [Int]

[Thomas Hartman]

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2007/5/4, Phlex <Phlex at telenet.be>:
> Hello all,
>
> I'm trying to learn haskell, so here's is my first newbie question.
> I hope this list is appropriate for such help requests.
>
> I'm trying to write a function with the signature [IO Int] -> IO [Int]
>
> Here is my first attempt :
>
> conv :: [IO Int] -> IO [Int]
> conv l = do val <- (head l)
>             return (val : (conv (tail l)))
>
> This does not work as I'm consing an Int to an (IO [Int]).
> So I tried this :
>
> conv2 :: [IO Int] -> IO [Int]
> conv2 l = do val <- (head l)
>              rest <- (conv2 (tail l))
>              return (val : rest)
>
> That works, but it won't work for infinite lists.
> How could I achieve the desired result ?
>
> Thanks in advance,
> Sacha
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