18 Jan
2016
18 Jan
'16
8:45 a.m.
On 18/01/16 05:12, David Feuer wrote:
-1. We already have a `<=` operator.
I would actively discourage from using that for implication - it is extremely counter-intuitive, and invites future headlines like "Self Driving Car Crushes Human Because In Haskell Logical Operators Are The Other Way Around" On 18/01/16 06:23, Jon Purdy wrote:
+1. “<=” has the wrong strictness. In “a `implies` b”, “b” should not be evaluated if “a” is false.
As a strawman, I’d propose that the Ord instance for Bool be changed—but this is more likely to break existing code, however slightly.
I think there's simply a difference between comparison and implication. For `<=` the existing strictness makes sense. For implication, a different strictness makes sense.