For example, it is possible to prove correctness of a function "negatedHead :: [Bool] -> Bool" by testing it on "True:undefined" and "False:undefined".
2009/10/12 Eugene Kirpichov <[email protected]>: > It is possible for functions with compact domain, not just finite. > > 2009/10/12 Joe Fredette <[email protected]>: >> In general? No- If we had an implementation of the `sin` function, how can >> testing a finite number of points along it determine >> if that implementation is correct for every point? >> >> For specific functions (particularly those with finite domain), it is >> possible. If you know the 'correct' output of every input, then testing each >> input and ensuring correct output will work. Consider the definition of the >> `not` function on booleans. The domain only has two elements (True and >> False) and the range has only two outputs (True and False), so if I test >> every input, and insure it maps appropriately to the specified output, we're >> all set. >> >> Basically, if you can write your function as a big case statement that >> covers the whole domain, and that domain is finite, then the function can be >> tested to prove it's correctness. >> >> Now, I should think the Muad'Dib would know that, perhaps you should go back >> to studying with the Mentats. :) >> >> /Joe >> >> >> >> On Oct 12, 2009, at 1:42 PM, muad wrote: >> >>> >>> Is it possible to prove correctness of a functions by testing it? I think >>> the >>> tests would have to be constructed by inspecting the shape of the function >>> definition. >>> >>> -- >>> View this message in context: >>> http://www.nabble.com/is-proof-by-testing-possible--tp25860155p25860155.html >>> Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com. >>> >>> _______________________________________________ >>> Haskell-Cafe mailing list >>> [email protected] >>> http://www.haskell.org/mailman/listinfo/haskell-cafe >> >> _______________________________________________ >> Haskell-Cafe mailing list >> [email protected] >> http://www.haskell.org/mailman/listinfo/haskell-cafe >> > > > > -- > Eugene Kirpichov > Web IR developer, market.yandex.ru > -- Eugene Kirpichov Web IR developer, market.yandex.ru _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
