[Haskell-cafe] What's the problem with iota's type signature?

[Lionel Barret de Nazaris]

On 28/05/2009 04:33, michael rice wrote:
> Still exploring monads. I don't understand why the type signature for 
> double is OK, but not the one for iota.
>
> Michael
>
> =================
>
> --double :: (Int a) => a -> Maybe b
> --double x = Just (x + x)
>
> iota :: (Int a) => a -> [b]
> iota  n = [1..n]
>
> --usage: [3,4,5] >>= iota
> --should produce [1,2,3,1,2,3,4,1,2,3,4,5]
>
>
iota is executed within the monad and as such must respect its law ?

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