Proposal #3339: Add (+>) as a synonym for mappend

Alexander Dunlap alexander.dunlap at gmail.com
Fri Jul 17 10:53:23 EDT 2009


On Tue, Jun 30, 2009 at 5:37 PM, Bryan O'Sullivan<bos at serpentine.com> wrote:
> Ticket: http://hackage.haskell.org/trac/ghc/ticket/3339
>
> From the ticket:
>
> This proposal was, I think, originally suggested by Jules Bean. The idea is
> to add two functions to the Data.Monoid module, (+>) and (<+), corresponding
> to different uses of mappend. These should not be methods of the Monoid
> typeclass, but top-level functions.
>
> I hope (but slightly doubt) that the visual nature of the two operators
> might help to counter the thought that monoids are just for gluing things
> together.
>
> (+>) :: (Monoid a) => a -> a -> a
> a +> b = a `mappend` b
>
> (<+) :: (Monoid a) => a -> a -> a
> a <+ b = b `mappend` a
>
> infixl 4 +>
> infixl 4 <+
>
> Proposed deadline: two weeks.
>
> If this looks reasonable, I'll attach darcs patches.
>

I (and apparently a lot of other people who commented on that ticket)
would prefer that (++) be generalized instead of introducing a new
operator.

Alex


More information about the Libraries mailing list