On Fri, Jul 12, 2013 at 6:39 PM, Jeff Walden <jwalden...@mit.edu> wrote: > On 07/12/2013 06:17 PM, Tab Atkins Jr. wrote: >> On Fri, Jul 12, 2013 at 5:15 PM, Domenic Denicola >> <dome...@domenicdenicola.com> wrote: >>> While I sympathize with the desire to make "integer" mean "mathematical >>> integer," I don't think it's going to work out very well. Nobody actually >>> cares about such functions, and you of course have the WATs of >>> >>> ```js >>> Number.isInteger(9007199254740992.5) === true >>> ``` >>> >>> since the runtime couldn't distinguish this from `9007199254740992`. >> >> This is what I was trying to point out as a ridiculous possibility in >> Jeff's idea, except he claimed it's what he actually wanted. ;_; > > Roughly no one will type something like that. :-) And if the "value" were > the result of an operation that lost precision, there's no way to tell that > with an API that tells you if the value was an integer.
Exactly, which is why we can only *accurately* answer for numbers <= 2^53-1. Anything larger might have lost precision. Technically, smaller things may lose precision as well - 2^52 + .5 == 2^52. But expecting precision out of decimals is a mugs game anyway. As long as you stick to integers, you can be sure of your precision for <= 2^53-1, but as soon as you hit 2^53, you're no longer sure. ~TJ _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
