[Haskell-cafe] Ord methods too strict?

Tom Ellis tom-lists-haskell-cafe-2017 at jaguarpaw.co.uk
Wed Jan 2 11:37:23 UTC 2019

On Wed, Jan 02, 2019 at 09:47:15AM +0000, V.Liepelt wrote:
> I am surprised to find that `False <= undefined = undefined`.
> What justifies (<=) to be strict in both arguments?

The implementation of the Ord instance for Bool is derived, as you can see


As for the justification, perhaps it's too much of a special case for only
one value of an enumeration to compare to undefined without crashing, and
perhaps it inhibits optimisation opportunities.


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