On Mon, Jan 15, 2018 at 2:30 PM, Jon Shier via swift-users
<swift-users@swift.org> wrote:
> This is pretty straightforward code, so am I missing something here?
Your '<' function does not define a valid strict total order.
For
let p1 = Point(1, 1)
let p2 = Point(0, 2)
neither of 'p1 < p2', 'p2 < p1', 'p1 == p2' is true. This is the root cause.
> static func <= (lhs: Point, rhs: Point) -> Bool {
> return lhs < rhs || lhs == rhs
> }
A faster way to compute it (with only one call to a user-defined
comparison operator) is to return '!(rhs < lhs)', which is wat the
standard library does, which is why you see the behavior that you are
seeing.
Dmitri
--
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <griboz...@gmail.com>*/
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