On Wed, Oct 2, 2013 at 3:49 PM, Niklas Haas <hask...@nand.wakku.to> wrote:
> On Wed, 2 Oct 2013 15:46:42 +0200, Stijn van Drongelen <rhym...@gmail.com> > wrote: > > I do think something has to be done to have an Eq and Ord with more > strict > > laws. > > > > * Operators in Eq and Ord diverge iff any of their parameters are bottom. > > * The default definitions of (/=), (<), (>) and `compare` are law. > > * (==) is reflexive and transitive > > * (<=) is antisymmetric ((x <= y && y <= x) `implies` (x == y)) > > * (<=) is 'total' (x <= y || y <= x) > > * (<=) is transitive > > > > Currently, reflexivity of (==) is broken in the Prelude (let x = 0/0 in x > > == x). I know this is for IEEE 754 compliance, but c'mon, this is > Haskell, > > we can have better ways of dealing with NaNs. > > Like making Double not be an instance of Eq? > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > Like making IEEE754 Doubles not an instance of Eq. Normal and denormal Doubles should have Eq instances.
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