Re: [Haskell-cafe] attoparsec double precision, quickCheck and aeson

On Jun 5, 2012, at 10:51 AM, Bryan O'Sullivan wrote:

On Tue, Jun 5, 2012 at 9:12 AM, Warren Harris wrote:

which helps in many cases, but for some the parsing seems bi-stable, alternating between two imprecise double values and causing the test to fail. I was wondering if anyone could suggest a better work-around for this problem, or explain why Attoparsec's double parser can't be isomorphic to haskell's.

If you need the full precision, use rational instead. The double parser is there because parsing floating point numbers is often a bottleneck, and double intentionally trades speed for precision.

I'm actually using Aeson and the parser it provides, so I don't really have the option of using rational.