On 24 April 2015 at 23:17, Tom Ellis
On Fri, Apr 24, 2015 at 11:06:07PM +1000, Ivan Lazar Miljenovic wrote:
What is the validity of defining an Ord instance for types for which mathematically the `compare` function is partially ordered?
I'm confused. What is supposed to be the result of `g1 <= g2` when `g1` and `g2` are not comparable according to the partial order?
With the proposed patch, it's the result of <= on the underlying [Int]Maps. Does the definition of Ord on Data.Map make sense? e.g. what should be the result of (fromList [(1,'a'), (2,'b'), (3, 'c')]) <= (fromList [(1,'a'), (4,'d')])? What about (fromList [(1,'a'), (2,'b'), (3, 'c')]) <= (fromList [(1,'a'), (2,'e')])? -- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com http://IvanMiljenovic.wordpress.com