Thomas Sandlaß wrote: > The benefit of a dedicated Interval type comes from supporting set > operations (&), (|) etc. which are still unmentioned in S03.
Have set operations been implemented in either Rakudo or Pugs? > BTW, > what does (1..^5).max return? I think it should be 4 because this > is the last value in the Range. Only in 4.7 ~~ 1..^5 does the five > matter. How does ~~ retrieve that information? For open intervals > the .min and .max methods should return the bound outside. Or better, > we should introduce infimum and supremum as .inf and .sup respectively. No offense, but I've noticed a tendency on your part to suggest highly technical names for things. "Infimum" and "supremum" may be technically accurate; but I wouldn't know, since I don't know for certain what they mean. "Min" and "max" may be misleading in terms of the specifics; but they get the general point across. >> I'm thinking of a Range-alike that one could use with Rat|Num or Instant >> etc, and not just Int etc. There would be operators to test membership of >> a value in the interval, and set-like operators to compare or combine >> intervals, such as is_inside, is_subset, is_overlap, union, intersection, >> etc. Such an interval would be what you use for inexact matching and would >> be the result of a ± infix operator or % postfix operator. Also, as Range >> has a .. constructor, this other type should have something. > > Since the Interval type shall be an addition to the Set subsystem I > propose the (..) Interval creation operator together with the open > versions. Admittedly that leaves (^..^) at a lengthy six chars. But > Jon's proposal of setting the by to zero isn't any shorter. Note that > the open versions are more important for Interval than they are for Range > because for Range you can always write it without ^ at the ends. In defense of my proposal, note that it _can be_ shorter if you say that :by defaults to zero when the endpoints are of continuous types such as Num, Instance, or Rat. That said, I admit that my proposal is something of a kludge - albeit te type of kludge that Perl tends to embrace (where reasonable, make a best guess as to the programmer's intentions; but provide a means gor him to be more explicit if your guess is wrong). -- Jonathan "Dataweaver" Lang
