[Haskell] Types of when and unless in Control.Monad

[Christian Höner zu Siederdissen]

* Julian Gilbey <julian at d-and-j.net> [22.04.2012 09:22]:
> On Sat, Apr 21, 2012 at 08:28:27PM -0500, Strake wrote:
> > On 21/04/2012, Andreas Abel <andreas.abel at ifi.lmu.de> wrote:
> > > to avoid silly "return ()" statements like in
> > >
> > >    when cond $ do
> > >      monadicComputationWhoseResultIWantToDiscard
> > >      return ()
> > 
> > (when cond ∘ void) monadicComputationWhoseResultIWantToDiscard
> > or
> > when cond $ () <$ monadicComputationWhoseResultIWantToDiscard
> 
> How is that simpler than
> 
>   when cond monadicComputationWhoseResultIWantToDiscard
> 
> which it would be with the suggested new type?
> 
>    Julian

Wouldn't "when_" and "unless_" or similar be better? I'd probably like
to have the compiler annoy me, since it is not clear that I want to
discard the result. If I really want to discard, I should have to make
it clear as there is probably a good reason for the inner function to
return a result in the first place?

Gruss,
Christian
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