Add Applicative instance for STM

[Bas van Dijk]

On Sun, May 16, 2010 at 7:10 PM, Ian Lynagh <igloo at earth.li> wrote:
> On Sun, May 16, 2010 at 06:36:56PM +0200, Bas van Dijk wrote:
>> On Sun, May 16, 2010 at 4:19 PM, Ross Paterson <ross at soi.city.ac.uk> wrote:
>> > It might be simpler to have Control/Applicative.hs import GHC.Conc and
>> > define the instance.
>>
>> The {-# SOURCE #-} import of Control.Applicative and the accompanying
>> boot file are indeed unfortunate. However, I like having the Functor,
>> Applicative and Monad instances in one place. But I can easily be
>> convinced if more people like it your way.
>
> I would prefer to avoid the import loop.

I just created a new patch that adds the Applicative and Alternative
instances for GHC.Conc.STM to Control.Applicative (guarded in a #ifdef
__GLASGOW_HASKELL__ block).

Bas