On Wed, 9 Jan 2008, Fernando Rodriguez wrote:
> I have the following type and function:
>
> data ConsCell a = Nil | Cons a (ConsCell a) deriving Show
> head' Nil = Nothing
> head' (Cons a _) = Just a
>
> Works fine, however, what's wrong with the following function?
>
> head''
> | Nil = Nothing
> | Cons a _ = Just a
Maybe you want
head''' x =
case x of
Nil -> Nothing
Cons a _ -> Just a
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