On Sat, Aug 15, 2009 at 10:15 AM, Brian Schott<[email protected]> wrote: > Raul, > > Would your suggestions be met if instead of > set =: ~. > the definition were > set =: (/:~)@~. > ?
Yes, except elements of sets must be boxed, so: set =: (/:~)@~...@boxxopen > And if that were correct, would "your" definition of > realset =: 3 : 0 > s =. y > for_k. i. >: L. y do. s =. sortset L:k s end. > ) > > be changed to > > realset =: 3 : 0 > s =. y > for_k. i. >: L. y do. s =. set L:k s end. NB. changed > ) > ? Well, I do not think realset should be used, in most contexts. However, for contexts where it's relevant (where every box represents an element of a set), I guess it would be realset =: 3 :'for_k. >: i. L. y do. y =. set L:k y end.' Note that this returns i.0 0 if given an argument which is not a set. I think that's appropriate. > I think this would enable the system to "compare" more complicated > sets like power sets, for example, whereas I am not sure how your > apparent preference would permit such "compare"s. I am using "compare" > in the sense that Kip combined u and n and iselementof. I do not see the difficulty. > My problem with sorting sets is that the user may have a good reason > for the unsorted order of a set and sorting might disrupt that > preference. The only good reason I can think of would be cases where the user is dealing with something which is not a set. In this case, the user should use the verb "set" to create the appropriate set. -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
