2009/2/20 David Menendez :

I like the Min/Max monoids, and the possibility of adding something like AddBounds (although I'd prefer a name like "Bounded"; "Bounded Integer" reads better than "AddBounds Integer").

We already have a Bounded typeclass, so things would get confusing. How about BoundsAdded Integer?

One possible snag is that, so far as I know, there's no explicit requirement that a type that instantiates Ord and Bounded should satisfy the laws,

   min maxBound a = a = min a maxBound    max minBound a = a = max a minBound

We're just assuming (reasonably) that instances will always work out that way. (Although, I guess we're making the same assumption with Sum and Prod.)

You could do something like class (Bounded a, Ord a) => BoundedOrd a where minB :: a -> a -> a minB a b | b == maxBound = a | a == maxBound = b | (a == minBound) || (b == minBound) = minBound | otherwise = min a b maxB :: a -> a -> a maxB a b | b == minBound = a | a == minBound = b | (a == maxBound) || (b == maxBound) = maxBound | otherwise = max a b And have the types inside Min and Max monoids need to be instances of this type. It depends how much we are trusting the implementors of min and max... It also doesn't stop people reimplementing them, perhaps we'll have to wait for conal's type class morphisms (I haven't fully digested these yet)? Will Pearson

On 2009-02-21, Benja Fallenstein wrote:

On Fri, Feb 20, 2009 at 2:57 PM, William Pearson wrote:

...

2009/2/20 David Menendez :

...

I like the Min/Max monoids, and the possibility of adding something like AddBounds (although I'd prefer a name like "Bounded"; "Bounded Integer" reads better than "AddBounds Integer").

We already have a Bounded typeclass, so things would get confusing. How about BoundsAdded Integer?

OrInfinity? :-)

I suppose Extended -- as in "extended real number" -- would not make the intent clear enough...

Borrowing from topology, "completion", or "compactified" suggest themselves, but I don't think they're clear enough in this context. WithBounds, BoundsAdded, or Bounded seem clear enough. I personally am not too concerned with the overlap with the Bounded typeclass. In fact, I think that agreeing is a nice concurrence of terminology. -- Aaron Denney -><-