Proposal: Bounded instance for IntSet (ticket #1953)

[John Meacham]

On Sun, Dec 02, 2007 at 03:45:40PM -0800, David Benbennick wrote:
> >From http://hackage.haskell.org/trac/ghc/ticket/1953 :
> 
> I propose to add a Bounded instance to IntSet.hs.
> 
> IntSet is in Ord, and there are only finitely many instances of
> IntSet. Therefore there is a min IntSet and a max IntSet. It turns out
> these bounds are very simple:
> 
> instance Bounded IntSet where
>     minBound = empty
>     maxBound = singleton maxBound

This seems fairly unintuitive me. the natural choices of minimum and
maximum bounds for a set would seem to be

singleton minBound vs singleton maxBound

or

empty vs universal (fromList [minBound .. maxBound]) set


the odd combination of the two proposed just feels off to me.

        John

-- 
John Meacham - ⑆repetae.net⑆john⑈