2014 Applicative => Monad proposal

Henning Thielemann lemming at henning-thielemann.de
Thu May 23 22:25:29 CEST 2013


On Thu, 23 May 2013, Nicolas Trangez wrote:

> On Thu, 2013-05-23 at 21:56 +0200, Henning Thielemann wrote:
>> I am only concerned with this one:
>>
>>> - Promote `join` into the Monad typeclass
>>
>> Currently, when I forget to implement the two essential Monad methods
>> 'return' and '>>=' in a Monad instance, I get a warning. However with the
>> mutual implementations of 'join' and '>>=' I do not get a warning but an
>> infinite loop. Similarly, I already had nasty bugs with (a-b) defaulting
>> to (a + negate b) and (negate a) defaulting to (0-a).
>
> http://hackage.haskell.org/trac/ghc/ticket/7633 might help.

Then I withdraw my concerns.



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