On Thu, 27 Oct 2005, Shae Matijs Erisson <[EMAIL PROTECTED]> wrote: > Joel Reymont <[EMAIL PROTECTED]> writes: > >> I could not understand how to define this for arbitraries of my >> choosing and Shae seems to have defined coarbitrary = error "Not >> implemented" :-). > > Coarbitrary is for generator transformers, see section 3.3 on page 5 of > the original paper http://www.md.chalmers.se/~koen/Papers/quick.ps
You need coarbitrary for Word32 if you want to generate arbitrary functions of type Word32 -> <something>. As you will see in the QuickCheck paper Coarbitrary instances can (often) be defined mechanically. I think QuickCheck 2 includes default coarbitrary methods implemented using generic classes (http://haskell.org/ghc/docs/latest/html/users_guide/generic-classes.html). -- /NAD _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe