Haskell Platform call for consensus: add transformers and revise the mtl package to depend on it

[Mario Blažević]

On 10-11-06 11:17 AM, Sebastiaan Visser wrote:
> Hi,
>
> Additionally, it would be very useful to have the MaybeT monad
> transformer included into mtl-2.
>
> While migrating my packages from transformers/monads-fd to the new
> mtl, the absence of MaybeT was the only problem I came across.


	What was your reason for doing this, if I may ask? Are there plans to 
deprecate transformers or monads-fd any time soon?

	I'm asking because my packages depend on transformers as well, and I 
don't see any reason to replace this dependency by mtl-2. If that is the 
recommended approach from now on, I can certainly do it.


>
> Cheers, Sebastiaan
>
> On Nov 6, 2010, at 3:26 PM, Ross Paterson wrote:
>> On Tue, Nov 02, 2010 at 02:17:03PM +0100, Johan Tibell wrote:
>>> This is a call for consensus for the following proposal:
>>>
>>> http://trac.haskell.org/haskell-platform/wiki/Proposals/transformers
>>>
>>>
>>>
Are there any unresolved concerns?
>>
>> Brent Yorgey's report raises one: the following functions, defined
>> in the transformers package as replacements for data constructors
>> for the base monads, should probably be re-exported by the new
>> mtl:
>>
>> Control.Monad.Cont: cont :: ((a ->  r) ->  r) ->  Cont r a
>> Control.Monad.RWS.Lazy: rws :: (r ->  s ->  (a, s, w)) ->  RWS r w
>> s a Control.Monad.RWS.Strict: rws :: (r ->  s ->  (a, s, w)) ->
>> RWS r w s a Control.Monad.Reader: reader :: (r ->  a) ->  Reader r
>> a Control.Monad.State.Lazy: state :: (s ->  (a, s)) ->  State s a
>> Control.Monad.State.Strict: state :: (s ->  (a, s)) ->  State s a
>> Control.Monad.Writer.Lazy: writer :: (a, w) ->  Writer w a
>> Control.Monad.Writer.Strict: writer :: (a, w) ->  Writer w a
>
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