Groups > comp.lang.java.programmer > #9617

Re: Immutable Datastructures with good Sharing

Date	2011-11-05 14:26 -0700
From	Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com>
Newsgroups	comp.lang.java.programmer
Subject	Re: Immutable Datastructures with good Sharing
References	(1 earlier) <stack-20111105042359@ram.dialup.fu-berlin.de> <j937eq$7k4$1@news.albasani.net> <4839047.311.1320512815263.JavaMail.geo-discussion-forums@pref15> <24CdnZZfrM8C5SjTnZ2dnUVZ_qmdnZ2d@posted.palinacquisition> <Lisp-20111105191449@ram.dialup.fu-berlin.de>
Message-ID	<D9qdnS2GZ_afNyjTnZ2dnUVZ_v6dnZ2d@posted.palinacquisition> (permalink)

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On 11/5/11 11:15 AM, Stefan Ram wrote:
> Peter Duniho<NpOeStPeAdM@NnOwSlPiAnMk.com>  writes:
>> What inherent contradiction?  Please cite an authoritative reference
>> that requires that the data structure known simply as a "stack" must be
>> implemented using mutable instances.
>
>    The most authoritative reference whatsoever, world-wide surely is
>    the renowned internet encyclopedia »Wikipedia«. And this says:
>
>        »The push operation adds a new item to the top of the stack«
>
> http://en.wikipedia.org/wiki/Stack_(abstract_data_type)
>
>    . »Add« is a /mutation/, it means to /change/ something by
>    /adding/ something to it.

Yes, add is a mutation.  It means to change something by adding 
something to it.  So, when you add two integers, why is that permitted, 
given that "int" is an immutable type?  When you add two strings (i.e. 
concatenate), why is that permitted, given that "String" is an immutable 
type?

Hint: you are confusing the question of changing something with the 
question of where the result of that change goes.

Certainly, there's nothing on Wikipedia (which frankly, is not "the most 
authoritative reference whatsoever" in any case) supports your claim.

I notice you also have failed to offer a more appropriate term.  Very 
telling.

>    In this context, the verb »add« has
>    the same meaning as in everyday language. The push operation
>    has no result specified, but it has an effect specified.
>
>    In the functional lanugage it is exactly the other way
>    round: It has a result specified, but no effect specified.
>
>> Requiring mutable instances would mean one could not, for example,
>> implement a stack at all in languages like Lisp or XSLT.
>
>    In Common Lisp, one /can/ implement mutable data structures.

Yes, there are variations of functional language that introduce 
mutability.  So?  That doesn't change the fact that mutability is not 
required in order to implement a stack.

Pete

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Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 04:03 +0100
  Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 12:42 +0100
    Re: Immutable Datastructures with good Sharing markspace <-@.> - 2011-11-05 09:35 -0700
      Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 19:33 +0100
        Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 14:42 -0400
          Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 19:52 +0100
            Re: Immutable Datastructures with good Sharing Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-05 19:32 +0000
            Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 15:31 -0400
              Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 20:50 +0100
                Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 16:26 -0400
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 21:35 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 21:38 +0100
                Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 16:59 -0400
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 22:06 +0100
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-05 16:41 -0400
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 21:42 +0100
                Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 17:11 -0400
            Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-05 16:20 -0400
              Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 21:33 +0100
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-05 16:38 -0400
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 21:41 +0100
                Re: Immutable Datastructures with good Sharing markspace <-@.> - 2011-11-05 17:20 -0700
                Re: Immutable Datastructures with good Sharing Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-11-05 22:13 -0300
                Re: Immutable Datastructures with good Sharing markspace <-@.> - 2011-11-05 20:05 -0700
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 10:27 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 10:14 +0100
    Re: Immutable Datastructures with good Sharing Lew <lewbloch@gmail.com> - 2011-11-05 10:06 -0700
      Re: Immutable Datastructures with good Sharing Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-11-05 10:55 -0700
        Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 19:30 +0100
          Re: Immutable Datastructures with good Sharing Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-11-05 18:16 -0400
            Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 23:20 +0100
            Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 23:38 +0100
        Re: Immutable Datastructures with good Sharing Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-11-05 17:47 -0300
        Re: Immutable Datastructures with good Sharing Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-11-05 14:26 -0700
      Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-05 16:14 -0400
  Re: Immutable Datastructures with good Sharing Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-11-05 14:35 -0700
    Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 22:42 +0100
      Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 22:50 +0100
      Re: Immutable Datastructures with good Sharing Peter Duniho <NpOeStPeAdM@NnOwSlPiAnMk.com> - 2011-11-05 14:51 -0700
        Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 22:58 +0100
          Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 23:03 +0100
            Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-05 23:07 +0100
            Re: Immutable Datastructures with good Sharing Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2011-11-06 09:44 +0200
              Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 10:22 +0100
                Re: Immutable Datastructures with good Sharing Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-11-06 09:05 -0400
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 14:16 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 14:22 +0100
                Re: Immutable Datastructures with good Sharing Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-06 14:30 +0000
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 16:02 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 16:08 +0100
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-06 16:18 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 16:54 +0100
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-06 17:31 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 22:33 +0100
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-06 16:47 -0500
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-06 16:58 +0100
                Re: Immutable Datastructures with good Sharing Tom Anderson <twic@urchin.earth.li> - 2011-11-07 01:01 +0000
                Re: Immutable Datastructures with good Sharing Lew <lewbloch@gmail.com> - 2011-11-06 17:26 -0800
                Re: Immutable Datastructures with good Sharing Tom Anderson <twic@urchin.earth.li> - 2011-11-07 23:45 +0000
                Re: Immutable Datastructures with good Sharing Lew <lewbloch@gmail.com> - 2011-11-06 14:44 -0800
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-06 17:51 -0500
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 01:28 +0100
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-06 19:50 -0500
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 02:13 +0100
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-06 20:20 -0500
                Re: Immutable Datastructures with good Sharing Lew <lewbloch@gmail.com> - 2011-11-06 17:29 -0800
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 11:22 +0100
                Re: Immutable Datastructures with good Sharing Tom Anderson <twic@urchin.earth.li> - 2011-11-06 23:02 +0000
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 00:32 +0100
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 01:10 +0100
                Re: Immutable Datastructures with good Sharing Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-07 10:24 +0000
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 11:52 +0100
                Re: Immutable Datastructures with good Sharing Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2011-11-07 11:12 +0000
                Re: Immutable Datastructures with good Sharing Arne Vajhøj <arne@vajhoej.dk> - 2011-11-07 17:24 -0500
                Re: Immutable Datastructures with good Sharing Giovanni Azua <bravegag@hotmail.com> - 2011-11-07 02:08 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 05:03 +0100
                Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 05:13 +0100
                Re: Immutable Datastructures with good Sharing Tom Anderson <twic@urchin.earth.li> - 2011-11-07 23:38 +0000
                Re: Immutable Datastructures with good Sharing Tom Anderson <twic@urchin.earth.li> - 2011-11-09 22:06 +0000
                Re: Immutable Datastructures with good Sharing Gene Wirchenko <genew@ocis.net> - 2011-11-09 18:02 -0800
  Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 00:28 +0100
    Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 00:39 +0100
      Re: Immutable Datastructures with good Sharing Arved Sandstrom <asandstrom3minus1@eastlink.ca> - 2011-11-06 20:57 -0400
        Re: Immutable Datastructures with good Sharing Jan Burse <janburse@fastmail.fm> - 2011-11-07 04:58 +0100
          Re: Immutable Datastructures with good Sharing Silvio Bierman <silvio@moc.com> - 2011-11-07 15:13 +0100
            Re: Immutable Datastructures with good Sharing Cthun <cthun_202@qmail.net.au> - 2011-11-07 12:54 -0500
              Re: Immutable Datastructures with good Sharing "B1ll Gat3s" <wm.g4t3s@m1cr0s0f7.c0m> - 2011-11-07 18:07 -0500
                Re: Immutable Datastructures with good Sharing B1ll Gat3s <wm.g4t3s@m1cr0s0f7.c0m> - 2011-11-07 22:07 -0500
                Re: Immutable Datastructures with good Sharing "B1ll Gat3s" <wm.g4t3s@m1cr0s0f7.c0m> - 2011-11-08 00:17 -0500
                Re: Immutable Datastructures with good Sharing thoolen <th00len@th0lenbot.thorium> - 2011-11-08 16:03 -0500
                Re: Immutable Datastructures with good Sharing Cthun <cthun_202@qmail.net.au> - 2011-11-08 15:49 -0500
                Re: Immutable Datastructures with good Sharing "B1ll Gat3s" <wm.g4t3s@m1cr0s0f7.c0m> - 2011-11-08 18:01 -0500
                Re: Immutable Datastructures with good Sharing thoolen <th00len@th0lenbot.thorium> - 2011-11-08 20:46 -0500
                Re: Immutable Datastructures with good Sharing "Cthun" <cthun_202@qmail.net.au> - 2011-11-08 22:43 -0500
                Re: Immutable Datastructures with good Sharing thoolen <th00len@th0lenbot.thorium> - 2011-11-09 08:28 -0500
                Re: Immutable Datastructures with good Sharing thoolen <th00len@th0lenbot.thorium> - 2011-11-08 16:00 -0500
  Re: Immutable Datastructures with good Sharing Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2011-11-07 08:46 -0800

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