Re: [Haskell-cafe] What's the advantage of writing Haskell this way?

I just tried to use the generic form with (Maybe a) and 'mconcat' prevented this from working, so that needs to be considered too. On Mon, May 30, 2011 at 10:53 PM, Casey McCann wrote:

On Mon, May 30, 2011 at 9:01 AM, John Ky wrote:

...

instance Monoid (Stream a) where     mempty = Chunks mempty     mappend (Chunks xs) (Chunks ys) = Chunks (xs ++ ys)     mappend _ _ = EOF

I guess, it shows my lack of experience in Haskell, but my question is, why is writing the code this way preferred over say writing it like this:

I don't care for the inconsistency in this example, using both mempty and (++). Your version is at least consistent, but I'd actually prefer to use mappend instead of (++) here, because it makes it clear that this isn't actually defining a "new" Monoid instance, just translating an existing instance for the constructor parameter to work for the surrounding data type.

- C.

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