On Tue, Apr 04, 2006 at 11:02:55AM -0700, Jonathan Lang wrote: : Will perl6 Sets include set negation and/or a universal set? In : effect, an internal flag that says, "this set contains every possible : element _except_ the ones listed"?

Arguably, that's what none() is. And all() is the only junction that is also a "normal" enumerated set. The any() junction is the set of sets that would intersect with the corresponding all() set without producing the null set. And the one() junction is the set of sets corresponding to the enumeration of all(). But this is all based on enumerated sets. Oddly missing are any Sets that are defined by rule. That would presumably take closures, though I suppose one can attempt to enumerate the closures that have to hold true and autothread through the calls to those closures... Can Russel be far behind? :-) Larry