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Message-ID: <5091390.GdagIssoVF@PointedEars.de>
From: Thomas 'PointedEars' Lahn <PointedEars@web.de>
Reply-To: Thomas 'PointedEars' Lahn <cljs@PointedEars.de>
Organization: PointedEars Software (PES)
Date: Fri, 23 Mar 2012 23:02:14 +0100
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Subject: Re: call by reference
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Andreas Bergmaier wrote:

> I know, JavaScript does not support call-by-reference. Every function
> invocation does call-by-value, even if that value is a reference value
> to an array-/function-/plain-Object, and not a primitive.

Correct.

> Yet, there is a javascript thing

There is no "javascript".

> that stores values by reference: the arguments object.

No.  According to ECMAScript Edition 5(.1) [ES5], section 10.6,  the 
Arguments object has special internal [[Get]] and [[Set]] methods to allow 
the observed behavior.
 
>   > function kill(a) { for (var i=0;i<a.length;i++) a[i]=false; }
>   > function x(a,b,c) { kill(arguments); return[a,b,c] };
>   > x(true,true,true)
>   [false, false, false]
> 
> I did not assign to a, b or c. Can this be termed "call-with-references"
> or something?

Yes (it can be termed something).

The behavior you observed has been removed for strict code in [ES5].


PointedEars
-- 
Anyone who slaps a 'this page is best viewed with Browser X' label on
a Web page appears to be yearning for the bad old days, before the Web,
when you had very little chance of reading a document written on another
computer, another word processor, or another network. -- Tim Berners-Lee