On Mon, 3 Dec 2007, Conal Elliott wrote:
I'm using the bounds for event occurrence times. Or, from another angle, for times associated with when values can become known. Pure values have time minBound, while eternally unknowable values (non-occurring events) have time maxBound. Hm. Now that I put it that way, I realize that I don't want to use existing minBound and maxBound if they're finite. (My event types are temporally polymorphic.) I'm mainly interested in Float/Double times, which have infinities in practice but apparently not guaranteed by the language standard. I guess I'll either (a) bake in Double (temporally monomorphic) and rely on infinities not guaranteed by the standard, or (b) keep temporal polymorphism and add infinities to time parameter. For now, (b).
Since you cannot rely on the existence of an infinity value for a floating point type with a particular behaviour - you can simply define you own type: data InfinityClosure a = NegativeInfinity | Finite a | PositiveInfinity