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

Hoogle is also helpful http://haskell.org/hoogle/?q=%5Bm+a%5D+-%3E+m+%5Ba%5D 2007/5/4, Phlex :

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 _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe