On Aug 25, 2008, at 4:41 PM, Waldemar Horwat wrote: > We're going round in circles on a few issues surrounding Decimal.
It seems to me people have reached the conclusion you already did on ===. I'm not sure anyone advocated otherwise (I've missed most 3.1 calls lately, so can't be sure). > Some of these have clear resolutions; others have a little wiggle > room. Here's my summary: Thanks, the FAQ format is helpful. I agree with your answers, but I have a couple of questions. > - Should decimal values behave as objects (pure library > implementation) or as primitives? > > If they behave as objects, then we'd get into situations such as > 3m != 3m in some cases and 3m == 3m in other cases. Also, -0m != > 0m would be necessary. This is clearly unworkable. What should be the result of (typeof 3m)? [snip] > - What should cross-type === do on 5 === 5m? > > These objects are of different types, so it should return false. Confusion: 5 is of "number" type (a primitive type, typeof agrees), so "These objects" should have been "These values" -- right? Sam and I, not going in circles (much), agree that typeof 3m should be "object", and that we add hardwired operator support for such Decimal objects. > - How should mixed type arithmetic work in general? > > There are a few consistent design alternatives: > > 1. Always disallow it. For consistency you'd have to disallow == > between Number and decimal as well. This was what Igor Bukanov and I were advocating last week. > 2. Allow it, converting to the wider type (Decimal128). There are > a couple design choices when doing the conversion: > 2a. Convert per the IEEE P754 spec: 5.1 turns into > 5.099999999999999644728632119949907m. This is how most programming > languages operate (C++, Java, Lisp, etc.) when converting among the > built-in floating point values (float -> double etc.). (I'm asking anyone who thinks so, as well as asking for your opinion:) Better than alternative 1? If so, why? > 2b. Convert the Number to a string and then to a Decimal: 5.1 > turns into 5.1m. As a special case, -0 would turn into -0m. This > might work, but I haven't thought through the implications of this > one. Interesting idea. /be _______________________________________________ Es-discuss mailing list Es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
