[Haskell-cafe] positive Int

[brad clawsie]

On Thu, Aug 02, 2007 at 12:17:06PM -0700, brad clawsie wrote:
> as far as i know, the haskell standard does not define a basic Int
> type that is limited to positive numbers.
> 
> would a type of this kind not potentially allow us to make stronger
> verification statements about certain functions?
> 
> for example, 'length' returns an Int, but in reality it must always
> return a value 0 or greater. a potential counter-argument would be the
> need to possibly redefine Ord etc for this more narrow type...


i suppose one could also say that the range [0..] of return values is
*implicit* in the function definition, so there is little value in
explicitly typing it given all of the hassle of specifying a new
typeclass etc

sorry, yes i am talking to myself