<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<br>
<br>
On 26.11.2008 05:32, Igor Stasenko wrote:
<blockquote
cite="mid:4a5f5f320811252032k1d9b31ecs288e82a9b4020a87@mail.gmail.com"
type="cite"><br>
<pre wrap=""><!---->Of course i know it. Just a small(talk) correction: classes are
objects as well and having state as well.
</pre>
<pre wrap="">
>From "The Early History of Smalltalk" by Alan Kay
1. Everything is an object
2. Objects communicate by sending and receiving messages (in terms of objects)
3. Objects has their own memory (in terms of objects)
----
4. Every object is an instance of class (which must be an object)
5. The class holds the shared behavior for its instances (in the form
of objects in a program list)
6. To eval a program list, control is passed to the first object and
the remainder is treated as its message
so, where in these statements you find anything about inheritance, or
something where it says that subclass(es) should have any assumptions
about the ways how superclass is storing its instances in memory, and
therefore a subclass allowed to directly manipulate the object's state
without consulting with superclass?
</pre>
</blockquote>
I'm afraid Alan wasn't as precise as he should have been here. In a
Squeak image, everything *IS REPRESENTED* by an object. I represent a
cat by an object, but that doesn't magically transform the purring cat
into a Squeak object. I *REPRESENT* a class by an object, but it is
confusing the issue to remove the distinction between the essence of a
class and its representation as an object. Many a discussion has gone
astray through this confusion. (Have you ever heard anyone say "class A
send a message to class B" when they mean "an instance of class A send
a message to an instance of class B"? )<br>
<br>
--Trygve<br>
<div class="moz-signature">-- <br>
<meta http-equiv="Content-Type" content="text/html; ">
<meta name="ProgId" content="Word.Document">
<meta name="Generator" content="Microsoft Word 10">
<meta name="Originator" content="Microsoft Word 10">
<link rel="File-List" href="TrygveSignature-filer/filelist.xml">
<title>-- </title>
<!--[if gte mso 9]><xml>
<w:WordDocument>
<w:SpellingState>Clean</w:SpellingState>
<w:GrammarState>Clean</w:GrammarState>
<w:HyphenationZone>21</w:HyphenationZone>
<w:PunctuationKerning/>
<w:DrawingGridHorizontalSpacing>6 pt</w:DrawingGridHorizontalSpacing>
<w:DrawingGridVerticalSpacing>6 pt</w:DrawingGridVerticalSpacing>
<w:DisplayHorizontalDrawingGridEvery>0</w:DisplayHorizontalDrawingGridEvery>
<w:DisplayVerticalDrawingGridEvery>3</w:DisplayVerticalDrawingGridEvery>
<w:UseMarginsForDrawingGridOrigin/>
<w:DoNotShadeFormData/>
<w:Compatibility>
<w:FootnoteLayoutLikeWW8/>
<w:ShapeLayoutLikeWW8/>
<w:AlignTablesRowByRow/>
<w:ForgetLastTabAlignment/>
<w:LayoutRawTableWidth/>
<w:LayoutTableRowsApart/>
<w:UseWord97LineBreakingRules/>
</w:Compatibility>
<w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel>
</w:WordDocument>
</xml><![endif]-->
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{mso-style-parent:"";
margin:0cm;
margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:12.0pt;
font-family:"Times New Roman";
mso-fareast-font-family:"Times New Roman";}
span.SpellE
{mso-style-name:"";
mso-spl-e:yes;}
span.GramE
{mso-style-name:"";
mso-gram-e:yes;}
/* Page Definitions */
@page
{mso-page-border-surround-header:no;
mso-page-border-surround-footer:no;}
@page Section1
{size:612.0pt 792.0pt;
margin:70.85pt 70.85pt 70.85pt 70.85pt;
mso-header-margin:35.4pt;
mso-footer-margin:35.4pt;
mso-paper-source:0;}
div.Section1
{page:Section1;}
-->
</style><!--[if gte mso 10]>
<style>
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Vanlig tabell";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";}
</style>
<![endif]--><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="2050"/>
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1"/>
</o:shapelayout></xml><![endif]-->
<div class="Section1">
<p class="MsoNormal" style=""><span class="SpellE"><span
style="font-size: 10pt; font-family: Arial;" lang="EN-GB">Trygve</span></span><span
style="font-size: 10pt; font-family: Arial;" lang="EN-GB">
Reenskaug<span style=""> </span>mailto: <span class="SpellE"><a class="moz-txt-link-abbreviated" href="mailto:trygver@ifi.uio.no">trygver@ifi.uio.no</a></span></span><span
style="font-size: 10pt; font-family: Arial;"><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span class="SpellE"><span class="GramE"><span
style="font-size: 10pt; font-family: Arial;" lang="EN-GB">Morgedalsvn</span></span></span><span
class="GramE"><span style="font-size: 10pt; font-family: Arial;"
lang="EN-GB">.</span></span><span
style="font-size: 10pt; font-family: Arial;" lang="EN-GB"> 5A <span
style=""> </span><a class="moz-txt-link-freetext" href="http://heim.ifi.uio.no/~trygver">http://heim.ifi.uio.no/~trygver</a><o:p></o:p></span></p>
<p class="MsoNormal" style=""><span
style="font-size: 10pt; font-family: Arial;">N-0378
Oslo<span style=""> </span>Tel: (+47) 22 49 57 27<o:p></o:p></span></p>
<p class="MsoNormal" style=""><span class="SpellE"><span
style="font-size: 10pt; font-family: Arial;">Norway</span></span><span
style="font-size: 10pt; font-family: Arial;"><o:p></o:p></span></p>
</div>
</div>
</body>
</html>