Augmenting Types
in [JavaScript]
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From: Thomas 'PointedEars' Lahn on 5 Jan 2010 16:46 Garrett Smith replied to a cancelled and deleted posting.
From: Jorge on 5 Jan 2010 17:56 On Jan 5, 2:55 am, Garrett Smith <dhtmlkitc...(a)gmail.com> wrote: > > Apple lies to the consumers about the technology. Could you please elaborate ? > Makes a web-incompatible browser Which is ... ? > patents the incompatibility You probably mean the touch/gestures iPhone JS API ? > prevents other > browser competition on iPhone. Here's a thought: design from scratch, build and try to sell your own "smartphone". Then allow your competitors to put their software in (Flash comes to my mind) so that you risk loosing control over your own invention. Bright idea, yeah. > The word "advertisement" comes from latin. The root word "advertise" > means "turn toward". And the saying think before you talk means exactly what it says. Cheers, -- Jorge.
From: Garrett Smith on 5 Jan 2010 17:58 Jorge wrote: > On Jan 5, 7:58 pm, Garrett Smith <dhtmlkitc...(a)gmail.com> wrote: >> Jorge wrote: >>> On Jan 5, 9:23 am, Jorge <jo...(a)jorgechamorro.com> wrote: >>>> On Jan 5, 8:07 am, Garrett Smith <dhtmlkitc...(a)gmail.com> wrote: >>>>> (...) >>>>> Accessing properties off the global object is slower than accessing >>>>> properties off a user defined object. >>>>> Access property off global object: >>>>> (...) >>>>> Access property off user-defined object: >>>>> (...) >>>> OMG. What are you saying ? >>> I mean, the code snippets that you've posted are comparing access time >>> to an identifier at the end of the scope chain (a global) versus an >>> identifier in the first link (a local var). That has nothing to do >>> with whether the object is or isn't "user defined". >> Which identifier at the end of the scope chain? >> >> Here is the example one more time: >> >> | Access property off global object: >> | (function(){ >> | var p = window; >> | var d = new Date; >> | for(var i = 0; i < 10000; i++) >> | p["d" + ".b" + i + ".c.d"] = i; >> | return new Date-d; >> | }()) > > Ok, Garret, excuse me. I misread the code. I though so. The only global identifier is `Date`, but that exists in both cases. Regardless, aliasing `Date` locally makes sense. > Yes, accessing window seems to take slightly longer than accessing {}. > I hope you're aware that p["d.bX.c.d"] has nothing to do with > p.d.bX.c.d, yes ? You're right. The property is weird. The reason for using that weird property name is have a fair comparison on a level field with speed test for the namespace function. The same name property assignment was copied from the other tests. Testing property access using no concatenation would read simpler, and would test purely property access speed, but would not compare as well to the `namespace` tests, which use some concatenation. The test for the namespace function uses a long concatenation, and so I used the exact same string. A more pure property-access test would not perform any string concatenation. -- Garrett comp.lang.javascript FAQ: http://jibbering.com/faq/
From: Thomas 'PointedEars' Lahn on 5 Jan 2010 18:16 Garrett Smith wrote: > Jorge wrote: >> On Jan 5, 7:58 pm, Garrett Smith <dhtmlkitc...(a)gmail.com> wrote: >>> Jorge wrote: >>>> On Jan 5, 9:23 am, Jorge <jo...(a)jorgechamorro.com> wrote: >>>>> On Jan 5, 8:07 am, Garrett Smith <dhtmlkitc...(a)gmail.com> wrote: >>>>>> (...) >>>>>> Accessing properties off the global object is slower than accessing >>>>>> properties off a user defined object. >>>>>> Access property off global object: >>>>>> (...) >>>>>> Access property off user-defined object: >>>>>> (...) >>>>> OMG. What are you saying ? >>>> I mean, the code snippets that you've posted are comparing access time >>>> to an identifier at the end of the scope chain (a global) versus an >>>> identifier in the first link (a local var). That has nothing to do >>>> with whether the object is or isn't "user defined". >>> Which identifier at the end of the scope chain? >>> >>> Here is the example one more time: >>> >>> | Access property off global object: >>> | (function(){ >>> | var p = window; >>> | var d = new Date; >>> | for(var i = 0; i < 10000; i++) >>> | p["d" + ".b" + i + ".c.d"] = i; >>> | return new Date-d; >>> | }()) >> >> Ok, Garret, excuse me. I misread the code. > > I though so. > > The only global identifier is `Date`, No, `window' is supposed to be a property of the global object, too. >> Yes, accessing window seems to take slightly longer than accessing {}. >> I hope you're aware that p["d.bX.c.d"] has nothing to do with >> p.d.bX.c.d, yes ? > > You're right. The property is weird. > > The reason for using that weird property name is have a fair comparison > on a level field with speed test for the namespace function. The same > name property assignment was copied from the other tests. The comparison is _not_ fair because `window' is not a (safe) reference to the global object. I had only cancelled my follow-up (that you had replied to anyway two hours later) because I observed, to my surprise, that `this' referring to the global object was (about 50%) slower than `global' where `global' was a property of the global object (even if it stored a reference to the global object) in Firebug (to which might the difference might be attributed; I would set up a Firebug-unrelated test case then). The rest of my points still apply for other cases than this: What matters here is _not_ whether the object-referring property is one of the global object but in how deep an execution context it is used (i.e., the length of the effective scope chain) and how many property accesses are necessary to retrieve the reference (i.e., the number of components -- and maybe the length of the expression, too, considering how hash tables work -- in the property accessor expression). PointedEars -- Danny Goodman's books are out of date and teach practices that are positively harmful for cross-browser scripting. -- Richard Cornford, cljs, <cife6q$253$1$8300dec7(a)news.demon.co.uk> (2004)
From: Jorge on 5 Jan 2010 18:43
On Jan 5, 11:56 pm, Jorge <jo...(a)jorgechamorro.com> wrote: > > Here's a thought: design from scratch, build and try to sell your own > "smartphone". Then allow your competitors to put their software in > (Flash comes to my mind) so that you risk loosing control over your > own invention. Bright idea, yeah. You ought to see what Larry Ellison says near the end (-5m40s) of the 2nd chapter of "the triumph of the nerds" about the "single worst mistake in history" IBM did with regards to the PC. Really. -- Jorge. |