On Thu, Feb 16, 2006 at 12:45:03PM +0000, Miles Sabin wrote: > Andres Loeh wrote, > > If a problem is decidable, it has the nice property that the problem > > (*not* the algorithm) can be used as a specification. Implementors > > are free to implement different algorithms, as long as they all solve > > the problem. If the problem is undecidable, how do you make sure that > > different compilers accept the same programs? If you don't want to > > find a subproblem that is decidable, you'll have to specify an > > algorithm, which is usually far more complicated, error-prone, and > > difficult to grasp for programmers. > > Again, I'm not sure that decidability helps practically here: we're not > interested in "compiler A and compiler B accept the same programs", > we're interested in "compiler A and compiler B accept some well defined > subset of possible programs in a reasonable amount of time and space".
But it seems that well defining that subset is equivalent to the problem of finding a suitable decidable algorithm. John -- John Meacham - ⑆repetae.net⑆john⑈ _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe