baffling manual sections

Alexander Dunlap alexander.dunlap at
Wed May 20 00:45:32 EDT 2009

On Tue, May 19, 2009 at 6:22 PM, Denis Bueno <dbueno at> wrote:
> On Tue, May 19, 2009 at 16:07, Jason Dusek <jason.dusek at> wrote:
>>  The former page also has a curious discussion of standalone
>>  deriving with a `for` keyword:
> Without this extension, adding an Eq implementation to a data type for
> which you do not have source requires an explicit class declaration,
> even if there is no reason the original data type author couldn't have
> written "deriving Eq".  Standalone deriving allows you to get the
> convenience of deriving classes everywhere, not just on datatypes for
> which you can obtain, and use, the source.
>                              Denis
> _______________________________________________

I think what he's referring to is that StandaloneDeriving actually has
the syntax

deriving instance Eq Foo


deriving Eq for foo


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