-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I am trying to understand the QuickCheck source in a bit of depth and I have noted that a Gen x is a function Int -> StdGen -> x, however, some of the combinators can at times, fail to ever produce a result by throwing an error. I include an example using ghci: *Test.QuickCheck> (f 0 (mkStdGen 0)) :: Int *** Exception: Prelude.(!!): negative index It seems this can be alleviated by changing Gen x to Int -> StdGen -> Maybe x and having the generator produce Nothing when a combinator fails. However, now the function promote cannot be written (I have tried and run into the conundrum of writing the function (a -> Maybe b) -> Maybe (a -> b)), which is used to generate functions. So, I'm caught on the fence about whether there is a possible improvement here (for example, should the elements function throw the error?), or if the current scenario is acceptable. I'm seeking comments about this, thanks! - -- Tony Morris http://tmorris.net/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIGjO6mnpgrYe6r60RAtohAKCBsl1lHxuNrBaLHuqwCN58PBHCIACbBALk YWkBkw9o9NUQbr+lgo0rXE0= =JQlH -----END PGP SIGNATURE-----