Haskell Platform call for consensus: add transformers and revise
the mtl package to depend on it
mblazevic at stilo.com
Mon Nov 8 13:22:59 EST 2010
On 10-11-06 11:17 AM, Sebastiaan Visser wrote:
> 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:
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
>> 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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