Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.mb-net.net!open-news-network.org!.POSTED!not-for-mail
From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups: comp.lang.javascript
Subject: Re: Can somebody explain this code
Date: Wed, 04 May 2016 05:51:40 +0200
Organization: PointedEars Software (PES)
Lines: 48
Message-ID: <3332181.Nmlc57RfOh@PointedEars.de>
References: <ncv2un$mlp$1@dont-email.me> <2380128.LjnWGdRavf@PointedEars.de> <nd1sgj$esr$1@dont-email.me> <3457976.2eFHA4iNFV@PointedEars.de> <nd9ipa$7r2$1@dont-email.me> <2497856.AOaF6Xk2y9@PointedEars.de> <nd9q0f$2h4$1@dont-email.me>
Reply-To: Thomas 'PointedEars' Lahn <cljs@PointedEars.de>
NNTP-Posting-Host: 90.228.197.178.dynamic.wless.zhbmb00p-cgnat.res.cust.swisscom.ch
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8Bit
X-Trace: gwaiyur.mb-net.net 1462333901 30463 178.197.228.90 (4 May 2016 03:51:41 GMT)
X-Complaints-To: abuse@open-news-network.org
NNTP-Posting-Date: Wed, 4 May 2016 03:51:41 +0000 (UTC)
User-Agent: KNode/4.14.2
Xref: csiph.com comp.lang.javascript:30388

Aleksandro wrote:

> On 27/03/16 20:07, Thomas 'PointedEars' Lahn wrote:
>> Aleksandro wrote:
>>> On 27/03/16 17:44, Thomas 'PointedEars' Lahn wrote:
>>>> Aleksandro wrote:
>>>>> On 24/03/16 16:30, Thomas 'PointedEars' Lahn wrote:
>>>>>>   var myFunc;
>>>>>>   myFunc = function () { alert("This is my anonymous function"); };
>>>>>>
>>>>>> (In that case, “myFunc” is assigned the “undefined” value first.)
>>>>> Would the VM actually assign undefined first? I doubt it.
>>>> On what grounds?
>>> Well, there's a thing called optimization... you know...
>> Although successive lines, they are not necessarily processed so.
> 
> But they might.

I am not convinced.

There are at least four points that you are overlooking here:

1. It was an *example* demonstrating functional equivalence of lines of
   source code.

2. myFunc = function () { alert("This is my anonymous function"); };
   var myFunc;
   
   is equivalent to the previous code, too.

3. There can be source code between declaration and assignment, and in the 
   assignment, referring to the variable.  The value of the variable has to
   be the “undefined” value then.

4. There is not only one virtual machine.  It need not even *be* a *virtual*
   machine; for example, Google V8 JIT-compiles source code directly into 
   machine code.

   <https://developers.google.com/v8/design>

Taking unnecessary risks based on wild guesses and wishful thinking is the 
mark of a wannabe.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.