Sam Ruby wrote: > Brendan Eich wrote: [...] >> The intuition depends on string equality and ToString in addition to >> numeric equality. But it turns out that a === b for any numbers a and >> b implies ToString(a) === ToString(b) (except, again, for the very >> small numbers David Jones pointed out). >> >> But Sam's decimal implementation has 1.1m === 1.10m. >> >> So the precise issue with "breaks arrays" is the proposal from Sam >> and Mike that ToString on a decimal preserve scale digits (I hope I'm >> using the right term). That breaks the a === b => o[a] is o[b] rule >> that exists today (modulo tiny values) for numbers a and b, when >> extended to decimals a and b. > > At the present time, strictly equals is approximately the "Object.eq". > There is no question that a.eq(b) => o[a] is o[b]. > > Permit me to be so bold as to propose a Gedanken Experiment? > > Is it ever anticipated that future editions of ECMAScript will allow > users to provide via multimethods alternative implementations for either > double equals or triple equals?
'==': that would potentially be useful, and I wouldn't want to rule it out at this stage (even though I'm not a particular fan of multimethods as they are defined in existing languages). Object.eq: no by definition. An EQ operation has a fixed semantics that tests identity without consulting its arguments or being overridable depending on their type. '===': that depends whether we want '===' to continue to be an approximation of EQ, with 0, -0, and NaN as the only special cases. -- David-Sarah Hopwood _______________________________________________ Es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
