[Haskell-beginners] Is it possible such Monad? (Baa)

[Baa]

Primary idea was to keep error messages. OK, I done it with `State`
monad :)

Thank you!

> Hi,
> 
> 1. I think your data type is isomorphic to
> 
> data Allpass w m a = Pass Bool (m a) w
> 
> 2. Maybe first try to write a Functor instance? Then you can find out
> what constraints are necessary for 'w' and 'm' to write it.
> 
> 3. What does this data type intend to represent?
> 
> Best,
> 
> toz
> 
> On Wed, Oct 25, 2017 at 5:32 AM <beginners-request at haskell.org> wrote:
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> >    1.  Is it possible such Monad? (Baa)
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> > Message: 1
> > Date: Wed, 25 Oct 2017 13:56:31 +0300
> > From: Baa <aquagnu at gmail.com>
> > To: The Haskell-Beginners Mailing List - Discussion of primarily
> >         beginner-level topics related to Haskell
> > <beginners at haskell.org> Subject: [Haskell-beginners] Is it possible
> > such Monad? Message-ID: <20171025135631.1f9913d2 at Pavel>
> > Content-Type: text/plain; charset=US-ASCII
> >
> > Hello All!
> >
> > Is it possible to write Monad for such type:
> >
> >   data Allpass w m a = Nopass (m a) w | Allpass (m a) w
> >
> > I can write (>>=), IMHO such type can not be Monad due to `w` is not
> > under `m` monad, right?
> >
> >
> > ===
> > Best regards, Paul
> >
> >
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