Control.Monad proposal: Add whenJust

[Ganesh Sittampalam]

-1 for the reasons given by Henning.

Also more polymorphic types generally cause worse error messages.

On 15/05/2013 17:14, Edward Kmett wrote:
> Personally, I'd be all for just moving Foldable (and Traversable) into
> the Prelude and retiring the monomorphic versions of the functions they
> supply. Both abstractions have born the test of time, and its hard to
> even envision Haskell without them at this point.
> 
> I'm somewhat leery that we coud get this proposal past the "but it makes
> it harder to introduce people to Haskell" backlash, but I'd
> wholeheartedly support it.
> 
> -Edward
> 
> 
> On Wed, May 15, 2013 at 10:25 AM, Ben Millwood <haskell at benmachine.co.uk
> <mailto:haskell at benmachine.co.uk>> wrote:
> 
>     On Wed, May 15, 2013 at 08:01:52AM +0300, Roman Cheplyaka wrote:
> 
>         * Ben Millwood <haskell at benmachine.co.uk
>         <mailto:haskell at benmachine.co.uk>> [2013-05-12 10:11:01+0100]
> 
>             You can mostly minimise harm by only hiding specific things, but
>             that's still more effort than I feel like I should have to
>             go to. I
>             think if we decide that the Foldable approach is useful
>             enough to go
>             in base, we should not make it a second-class citizen.
> 
> 
>         ... except it is in base already :)
> 
>         Roman
> 
> 
>     Yeah, sorry, to clarify: *since* we think it is important enough to
>     go in base, we should make it easy to use as well.
> 
> 
>     _________________________________________________
>     Libraries mailing list
>     Libraries at haskell.org <mailto:Libraries at haskell.org>
>     http://www.haskell.org/__mailman/listinfo/libraries
>     <http://www.haskell.org/mailman/listinfo/libraries>
> 
> 
> 
> 
> _______________________________________________
> Libraries mailing list
> Libraries at haskell.org
> http://www.haskell.org/mailman/listinfo/libraries
>