Math ugliness.
in [JavaScript]
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From: Thomas 'PointedEars' Lahn on 17 Feb 2010 00:30 kangax wrote: > RobG wrote: >> Jorge wrote: >>> Do you think -as I do- that the Math object is an ugly artifact ? >>> Well, here's a nice way of getting rid of it : >>> >>> Number.prototype.sin= function () { return Math.sin(+this); }; >> >> I'm curious about the use of unary +. Presumably the identifier is >> resolved to a number primitive in the first place, otherwise x.sin >> wouldn't resolve to Number.prototype.sin. > > I was curious about this too. > > I'm guessing ToNumber conversion is there to make method intentionally > generic, similar to, say, `String.prototype.trim` from ES5, which passes > its this value through ToString before trimming a value. It is still superfluous as the methods of `Math' already call ToNumber() on each of their arguments. PointedEars -- Prototype.js was written by people who don't know javascript for people who don't know javascript. People who don't know javascript are not the best source of advice on designing systems that use javascript. -- Richard Cornford, cljs, <f806at$ail$1$8300dec7(a)news.demon.co.uk>
From: kangax on 17 Feb 2010 00:59 On 2/17/10 12:30 AM, Thomas 'PointedEars' Lahn wrote: > kangax wrote: > >> RobG wrote: >>> Jorge wrote: >>>> Do you think -as I do- that the Math object is an ugly artifact ? >>>> Well, here's a nice way of getting rid of it : >>>> >>>> Number.prototype.sin= function () { return Math.sin(+this); }; >>> >>> I'm curious about the use of unary +. Presumably the identifier is >>> resolved to a number primitive in the first place, otherwise x.sin >>> wouldn't resolve to Number.prototype.sin. >> >> I was curious about this too. >> >> I'm guessing ToNumber conversion is there to make method intentionally >> generic, similar to, say, `String.prototype.trim` from ES5, which passes >> its this value through ToString before trimming a value. > > It is still superfluous as the methods of `Math' already call ToNumber() on > each of their arguments. Ah, yes, 15.8.2. Good point. -- kangax
From: kangax on 17 Feb 2010 01:01 On 2/17/10 12:14 AM, Thomas 'PointedEars' Lahn wrote: > Cody Haines wrote: > >> Jorge<jorge(a)jorgechamorro.com> wrote: >>> Do you think -as I do- that the Math object is an ugly artifact ? >>> Well, here's a nice way of getting rid of it : >>> >>> Number.prototype.sin= function () { return Math.sin(+this); }; >>> Number.prototype.asin= function () { return Math.asin(+this); }; >>> Number.prototype.pow= function (p) { return Math.pow(+this, p); }; >>> Number.prototype.sqrt= function () { return Math.sqrt(+this); }; >>> Number.prototype.rnd= function () { return this*Math.random(); } >>> >>> etc.. >>> >>> x= 16; >>> x.sqrt() >>> --> 4 >>> >>> x="256"; >>> (+x).pow(2) //be sure to call the right .proto >>> --> 65536 >>> >>> (1.234).sin().asin() >>> --> 1.234 >>> >>> 1..asin() * 2 >>> -> 3.141592653589793 >>> >>> (2).pow(10) >>> --> 1024 >>> >>> 2..pow(10).sqrt() >>> --> 32 >>> >>> (100).rnd() >>> -> 0<= n< 100 >>> [...] >> >> Just out of curiosity, does IE support this? I don't see why it >> wouldn't, just making sure > > JScript 5.6.6626 as of IE 6.0.2800.1106 supports this. It stands to reason > that later versions of JScript and Internet Explorer, therefore other > MSHTML-based browsers, would also support this (I cannot test them here > yet). > > In fact, given that, according to Editions 3 and 5 of the ECMAScript > Language Specification, when evaluating the CallExpression's > /MemberExpression/ any primitive value would be converted into an > appropriate value of type Object (ES3/5, 11.2.3, 11.2.1, and 9.9), this > SHOULD work everywhere where `Number.prototype' is supported (which AFAIK > excludes only JavaScript 1.0 as of Netscape 2.x, and JScript 1.0 as of IE > 3.0 and IIS 3.0 ).¹ Tests with JavaScript, Apple JSC, Opera ECMAScript, > and KJS confirmed this a while ago; I could also confirm it for Google V8 > 2.0 as of Chrome 5.0.307.7 by now. (In fact, this idea is anything but > original.) [...] > ___________ > ¹ To be sure of that, I have debugged the algorithms of ECMAScript Ed. 5, > and compared with Ed. 3; I can post more detailed results of my > research if anyone is interested. I'm interested. -- kangax
From: Jorge on 17 Feb 2010 03:22 On Feb 17, 4:10 am, RobG <rg...(a)iinet.net.au> wrote: > On Feb 17, 9:23 am, Jorge <jo...(a)jorgechamorro.com> wrote: > > > Hi, > > > Do you think -as I do- that the Math object is an ugly artifact ? > > Well, here's a nice way of getting rid of it : > > > Number.prototype.sin= function () { return Math.sin(+this); }; > > I'm curious about the use of unary +. Presumably the identifier is > resolved to a number primitive in the first place, otherwise x.sin > wouldn't resolve to Number.prototype.sin. > > Or have I missed something? I believe it gets -automatically- wrapped in an object just before -in order to do- the property lookup... ¿? > [...] > > > x="256"; > > (+x).pow(2) //be sure to call the right .proto > > --> 65536 > > So if x must be a number in order for the right property to be found, > why must it also be converted inside the function? I did that because I recall that new Number(3) !== new Number(3): IOW, because "this" is -supposedly- an object. This idea occurred to me yesterday late at night while watching Crockford on JS video #2, and I just posted it here on the fly without much/any further ado/testing. -- Jorge.
From: Jorge on 17 Feb 2010 03:36
On Feb 17, 6:14 am, Thomas 'PointedEars' Lahn <PointedE...(a)web.de> wrote: > > (...) In fact, this idea is anything but original. (...) And then came Pointy, decided to spoil the fun... :-) I've never seen it before.. who, where, when ? Have you got any urls, plz ? -- Jorge. |