[Haskell-cafe] Libraries of standard QuickCheck properties

[Luke Palmer]

2008/8/21 Sean Leather <leather at cs.uu.nl>:
> This in response to a comment on a GHC ticket [1]. I thought it was
> interesting enough to warrant general discussion.
>
>> Comment (by JeremyShaw):
>>
>>  > Also, where does the H98 report say all instances of Eq must be
>>  transitive, reflexive, symmetric, and antisymmetric? It just says "The Eq
>>  class provides equality (==)..", whatever that might mean :-)
>>
>>  Well, it does not say it explicitly, but I suspect H98's usage of Eq
>>  implicitly demands those laws be followed.
>
> Indeed. The same goes for the implicit law that (x /= y) /= (x == y), since
> both (/=) and (==) can be overridden. [2]
>
>> Hopefully in Haskell' the laws
>>  will not only be stated, but there will be some QuickCheck-style
>>  properties you can use to test your own instances ;)
>
> This is an interesting thought. Has there been any work towards collecting
> properties written with QuickCheck (or similar) into a reusable chunk of
> some form?

Yes, it's in development, called 'checkers'.  code.haskell.org/checkers

Luke