[Haskell-cafe] ANN: convertible (first release)

[Michael D. Adams]

On Wed, Jan 28, 2009 at 5:28 PM, wren ng thornton <wren at freegeek.org> wrote:
> John Goerzen wrote:
>> wren ng thornton wrote:
>> I wonder if you would consider submitting a patch to base?  It seems
>> that this is a sore problem there, and ideally should be dealt with
>> properly in base.
>
> As Bertram Felgenhauer says, it's not as easy as fixing base; the problem is
> an error in the Haskell98 specification. The Float and Double types contain
> exceptional values which cannot be represented in Rational (by definition).
> The only Haskell98 solution is to raise an error when attempting to convert
> those values into Rational, which isn't much of an improvement.

Is there a good reason why Rational is defined in a way that it can
not represent Nan, Inf and -Inf? (Any other exceptional values I
forgot?)  Would fixing the definition so that it can represent those
values be sufficient to fix this entire problem?

Michael D. Adams
mdmkolbe at gmail.com