Re: Maximum and Minimum monoids

+1 for something like this. I've written these at least once, and encountered them on a few more occasions. I would prefer specific types as Roman suggests, I think. I prefer to match on Plus/MinusInfinity rather than going via Maybe. John L.

From: Roman Cheplyaka Subject: Re: Maximum and Minimum monoids

To: Gabriel Gonzalez

Cc: libraries@haskell.org Message-ID: <20121227202510.GA24842@sniper> Content-Type: text/plain; charset=us-ascii

Wouldn't it be better to have a real algebraic type instead of wrapping Maybe?

Something like

data Maximum a = MinusInfinity | Maximum a data Minimum a = PlusInfinity | Minimum a

Maximum x is more concise than Maximum (Just x), and MinusInfinity is more descriptive than Maximum Nothing. getMaximum/getMinimum functions can still return Maybes.

Anyway, I'm +1 to having something along these lines.

Roman