Re: Edison RC3

On Apr 5, 2006, at 11:34 AM, Nils Anders Danielsson wrote:

On Wed, 05 Apr 2006, Robert Dockins wrote:

...

So you think it would be clearer if I just ignored bottom as well?

It would be imprecise instead of wrong. :)

I suppose if you force the reader to evaluate documentation non- deterministically, then you can presume your documentation is correct if there is any correct interpretation they might have chosen ;-)

Another option is to go for some sort of approximate semantics which still includes bottoms. You could for instance assume that bottom = const bottom, and state your results in that context. Verifying the results would still mean a lot of work, though.

Humm. Well, I'd actually prefer not to have to say anything about bottom. I'm really only interested in telling the user that output of a function is not completely determined by the contract. <shakes fist> Dang you bottom! I'll have to think some more about what to do here and see if there's a nice way to sidestep the issue entirely.

By the way, does your library have a QuickCheck test suite?

Yes indeed.

In that case it is often not too hard to test properties involving bottoms. I have a library which may be of help: http://www.cs.chalmers.se/~nad/software/ChasingBottoms/docs/

Nice! I notice however, that it relies on exceptions and implicit parameters. I'm willing to accept less portability in the test suite than in the library proper, but I feel that implicit parameters are pushing it a bit, since they appear unlikely to make it into H'.

-- /NAD

Rob Dockins Speak softly and drive a Sherman tank. Laugh hard; it's a long way to the bank. -- TMBG