On 16 December 2011 05:26, Brent Yorgey wrote:

I, for one, would be quite in favor of changing the current Monoid (Maybe a) instance to correspond to the failure-and-prioritized-choice semantics

So lets do this. Some questions: 1) What about the First type? Do we {-# DEPRECATE #-} it? 2) What about the Last type? It could be deprecated in favor of Dual. 3) Do we need a new type (like the current Maybe) for lifting semigroups into a Monoid? IMHO we don't since the semigroup package does a better job with the Option type (like Brent mentioned). 4) How much code will break from this change? 5) Anyone up for proposing this to libraries@haskell.org? Regards, Bas