[Haskell-beginners] Pipe and typeclasses

[Emmanuel Surleau]

Thanks! Actually, I read about them some time ago (last year?) but prompty
forgot again, it looks like.

On Tue, Jul 23, 2013 at 9:56 PM, Karol Samborski <edv.karol at gmail.com>wrote:

> 2013/7/23 Emmanuel Surleau <emmanuel.surleau at gmail.com>
>
>> Hello,
>>
>> I have seen from time to time the pipe symbol in type signatures, like so:
>>
>>   class Monad m => MonadReader r m | m -> r where
>>
>> How should I interpret that ? Or more to the point, how does the compiler
>> interpret it?
>>
>
> Hi Emmanuel!
>
> The pipe symbol is for a functional dependency:
> http://www.haskell.org/haskellwiki/Functional_dependencies
>
>
Thanks Karol! I actually read about the concept some months ago, but
apparently forgot about it again.

Cheers,

Emm
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