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Re: What's a good Javascript book?

From Stefan Weiss <krewecherl@gmail.com>
Newsgroups comp.lang.javascript
Subject Re: What's a good Javascript book?
Date 2012-10-09 13:12 +0200
Organization albasani.net
Message-ID <k510r9$1tp$1@news.albasani.net> (permalink)
References <a30f024f-096a-48c2-a1fb-c1465c8e4267@googlegroups.com> <k4umv3$o27$1@news.albasani.net> <QzABPTFMH$cQFwLs@J.A830F0FF37FB96852AD08924D9443D28E23ED5CD>

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On 2012-10-09 11:43, John G Harris wrote:
> On Mon, 8 Oct 2012 at 16:11:47, in comp.lang.javascript, Stefan Weiss
> wrote:
> 
>   <snip>
>>(Objects may be implemented as some
>>form of hash table or hash map internally, but that's of no consequence
>>to users.)
>   <snip>
> 
> This is unlikely, as it happens.
> 
> One of the proposals for the abandoned ES4 was for 'for-in' to access
> properties in insertion order. Apparently enough web designers relied on
> this undocumented behaviour in NS and IE that it was thought worth
> standardising.
> 
> A hash table implementation would make this behaviour difficult to
> implement. Telling annoyed web designers whose pages stop working that
> it's their own fault for relying on undocumented behaviour has never
> been popular.

Alright, now you've made me curious :)

I had an older version of the Rhino source code lying around, and as you
said, the notion that JavaScript objects are internally modeled as
derivatives of HashMaps is too simplistic - by far! From what I can see
at a quick glance, the internal representations of objects are derived
from the ScriptableObject class, which defines its own Slot inner class
to store JS properties. The slots each have "next" and "orderedNext"
properties, but there's so much else going on in there that it would
take me too long to completely understand it (including lookups in the
prototype chain, DontEnum, getters, etc). Ultimately, however, the
actual current values appear to be stored in an ordinary HashMap named
associatedValues.

- stefan

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Thread

What's a good Javascript book? I Am Here <iamhereintheworld@gmail.com> - 2012-10-08 06:35 -0700
  Re: What's a good Javascript book? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-08 13:52 +0000
    Re: What's a good Javascript book? "Jukka K. Korpela" <jkorpela@cs.tut.fi> - 2012-10-08 17:03 +0300
      Re: What's a good Javascript book? Tim Streater <timstreater@greenbee.net> - 2012-10-08 15:22 +0100
        Re: What's a good Javascript book? "Mel Smith" <med_cutout_syntel@aol.com> - 2012-10-08 08:56 -0600
  Re: What's a good Javascript book? Stefan Weiss <krewecherl@gmail.com> - 2012-10-08 16:11 +0200
    Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-09 10:43 +0100
      Re: What's a good Javascript book? Stefan Weiss <krewecherl@gmail.com> - 2012-10-09 13:12 +0200
        Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-10 15:32 +0100
          Re: What's a good Javascript book? Stefan Weiss <krewecherl@gmail.com> - 2012-10-10 20:13 +0200
            Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-11 14:28 +0100
      Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-09 17:56 +0100
        Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-10 00:32 +0200
          Re: What's a good Javascript book? Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-10-09 16:37 -0700
          Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-10 06:44 +0100
            Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-10 20:09 +0200
            Re: What's a good Javascript book? Dr J R Stockton <reply1241@merlyn.demon.co.uk.invalid> - 2012-10-11 19:43 +0100
  Re: What's a good Javascript book? Gregor Kofler <usenet@gregorkofler.com> - 2012-10-08 16:21 +0200
  Re: What's a good Javascript book? "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2012-10-08 07:56 -0700
  Re: What's a good [JavaScript] book? Matt McDonald <matt@fortybelow.ca> - 2012-10-08 11:38 -0400
    Re: What's a good [JavaScript] book? Matt McDonald <matt@fortybelow.ca> - 2012-10-08 11:42 -0400
      Re: What's a good [JavaScript] book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-10 00:41 +0200
  Re: What's a good Javascript book? Danny <dann90038@gmail.com> - 2012-10-08 11:57 -0700
    Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-08 20:39 +0100
  Re: What's a good Javascript book? I Am Here <iamhereintheworld@gmail.com> - 2012-10-09 06:19 -0700
    Re: What's a good Javascript book? Gregor Kofler <usenet@gregorkofler.com> - 2012-10-09 18:43 +0200
      Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-09 10:06 -0700
        Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-09 11:43 -0700
          Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-09 20:07 +0100
          Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-09 13:40 -0700
        Re: What's a good Javascript book? Gregor Kofler <usenet@gregorkofler.com> - 2012-10-09 20:55 +0200
          Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-09 13:45 -0700
          Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-10 04:31 -0700
      Re: What's a good Javascript book? Stefan Weiss <krewecherl@gmail.com> - 2012-10-09 20:09 +0200
        Re: What's a good Javascript book? Gregor Kofler <usenet@gregorkofler.com> - 2012-10-09 21:01 +0200
          Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-09 13:50 -0700
      Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-10 15:26 +0100
        Re: What's a good Javascript book? Tim Streater <timstreater@greenbee.net> - 2012-10-10 15:58 +0100
          Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-11 14:39 +0100
            Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-11 06:52 -0700
              Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-11 17:13 +0100
                Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-11 10:39 -0700
                Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-12 10:37 +0100
                Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-12 07:11 -0700
                Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-13 10:53 +0100
                Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-12 09:49 -0700
                Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-12 10:22 -0700
                Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-12 13:17 -0700
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-12 20:32 +0100
                Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-13 10:50 +0100
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-13 19:45 +0100
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-13 21:55 +0200
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-13 21:52 +0100
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-13 23:49 +0200
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-13 23:57 +0200
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-13 23:34 +0100
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-14 02:09 +0200
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-14 00:00 +0100
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-14 01:58 +0200
                Re: What's a good Javascript book? Patricia Shanahan <pats@acm.org> - 2012-10-14 07:17 +0100
                Re: What's a good Javascript book? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2012-10-15 01:17 +0200
                Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-14 13:40 +0100
                Re: What's a good Javascript book? Gene Wirchenko <genew@ocis.net> - 2012-10-14 19:03 -0700
                Re: What's a good Javascript book? John G Harris <john@nospam.demon.co.uk> - 2012-10-15 10:42 +0100
    Re: What's a good Javascript book? "Evertjan." <exxjxw.hannivoort@inter.nl.net> - 2012-10-09 22:49 +0200
  Re: What's a good Javascript book? Scott Sauyet <scott.sauyet@gmail.com> - 2012-10-09 12:00 -0700
  Re: What's a good Javascript book? I Am Here <iamhereintheworld@gmail.com> - 2012-10-16 06:57 -0700

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