[Haskell-cafe] is proof by testing possible?

[Dan Piponi]

I'm making the same mistake repeatedly. In both my mails there are
places where I said (a,b) or (b,a) when I meant (a,a).
--
Dan

On Mon, Oct 12, 2009 at 11:09 AM, Dan Piponi <dpiponi at gmail.com> wrote:
> Joe,
>
>> On Mon, Oct 12, 2009 at 11:03 AM, Joe Fredette <jfredett at gmail.com> wrote:
>> I completely forgot about free theorems! Do you have some links to resources
>> -- I tried learning about them a while
>> ago, but couldn't get a grasp on them... Thanks.
>
> There is Wadler's paper but I do find it tricky:
> http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.38.9875
>
> You can play with the generator here:
> http://linux.tcs.inf.tu-dresden.de/~voigt/ft/
> The results can look unreadable at first, but I find that if I copy
> them onto paper and do all of the remaining substitutions manually
> (like I had to do with (a,b) -> (b,a)) you end up with something
> readable. If you keep doing this you'll get a good intuition for what
> the free theorem for a type will look like.
> --
> Dan
>