On Tuesday 21 October 2008 07:42:48 Abdulaziz Ghuloum wrote: > On Oct 21, 2008, at 8:03 AM, Ken Dickey wrote: > > Doesn't it make more sense to require existence for comparison? > > Existence of one ordered pair does not matter much. You need > to either prove the existence of a counter example to produce > #f, or to prove universality (e.g., with for-all) to produce #t. > > You can't say: I'll require that all adjacent pairs are ordered, > except when there are no pairs, where I'll switch my logic and > demand the existence of an ordered pair. > > > (define (monotonic? ordered? sequence) > > (let ( [list-of-pairs (pairs-in sequence)] ) > > (if (null? list-of-pairs) > > #f > > (for-all > > (lambda (pair) (ordered? (car pair) (cdr pair))) > > list-of-pairs)) > > ) ) > > You just made an arbitrary exception to the rule by providing > an arbitrary value for the (null? ---) case. I don't see that > following your rule of least surprise. > > Aziz,,,
No. Actually, I'd like a holds-for-all which returns #f as the base case. -KenD _______________________________________________ r6rs-discuss mailing list r6rs-discuss@lists.r6rs.org http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
