> so, I either I don't agree or I don't understand It was the latter - I understand and agree now :)
On Mon, Jul 15, 2013 at 10:03 AM, Andreas Rossberg <[email protected]>wrote: > On 15 July 2013 15:49, Jeremy Martin <[email protected]> wrote: > >> (a === b) >= (new Symbol(a) === new Symbol(b)) > > > > Not sure I follow... so, I either I don't agree or I don't understand :). > > I'm having to dig deep to remember my math vocab here, but I think it > may be > > most correct to say that the Symbol constructor, when passed an argument, > > should be injective [1]. That is, > > > > 1. let F = new Symbol > > 2. if a = b, then F(a) = F(b) > > 3. if a != b, then F(a) != F(b) > > I agree, but the problem is that JavaScript's === is not an > equivalence relation, due to the dreaded NaN !== NaN that IEEE > invented in some delirium. So you cannot define injectivity based on > it. You merely get an implication for the above, which is what the >= > was supposed to encode. Object.is OTOH implements a proper equivalence > relation, i.e. a "=" in the mathematical sense. It only differs from > === by having a sane semantics for NaN. > > But as I said, I was merely picking a nit. > > /Andreas > -- Jeremy Martin 661.312.3853 http://devsmash.com @jmar777
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