[Haskell-beginners] Re: Apparent bug

[Ozgur Akgun]

On 16 November 2010 18:40, Russ Abbott <russ.abbott at gmail.com> wrote:

> why isn't
>
> instance Show Test
>
> interpreted to mean
>
> data Test = Test deriving (Show)
>
> *
> -- Russ *
>

One of them is declaring an instance, the other is asking the compiler
derive an instance declaration for you. I don't know why the empty one is
interpreted to be an instance deriving. Maybe because in such a case there
would be no way to declare an empty instance?

In addition, there is yet another similar syntax. See stand-alone
deriving<http://haskell.org/ghc/docs/6.12.2/html/users_guide/deriving.html>
.

Ozgur
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