[Haskell-cafe] New version of itself

martin martin.drautzburg at web.de
Mon Jun 6 09:11:09 UTC 2016

Applicative does the trick. But using do-notation was my first attempts, but I could not figure it out. Can you see how
to do this (other than using `ap`)?

Am 06/06/2016 um 10:20 AM schrieb Erik Hesselink:
> Since `Mealy a` is an instance of `Applicative` you can do:
>   (&&) <$> m1 <*> m2
> It's also a monad, so do notation would also work.
> Erik
> On 6 June 2016 at 10:00, martin <martin.drautzburg at web.de> wrote:
>> Carl,
>> thanks for pointing me towards mealy machines.
>> Maybe you can help me with this one: I am trying to compose two mealy machines into one. Suppose I have
>> m1 :: Mealy a Bool
>> m2 :: Mealy a Bool
>> now I want a combinded mealy machine which outputs True when both m1 and m2 return True and False otherwise. I can write
>> this using runMealy. But this looks awkward, because it is a bare-bones implementation and doesn't make use of any of
>> the typeclasses Mealy is a member of. I.e. the machines package is basically not used at all.

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