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<DIV><FONT size=2 face=Arial>Hi,</FONT></DIV>
<DIV><FONT size=2 face=Arial>IMO, an object is something that preserves identity
under the pov</FONT></DIV>
<DIV><FONT size=2 face=Arial> of an objerver (the</FONT><FONT size=2
face=Arial> self that reflectOn/know/named "the object");</FONT></DIV>
<DIV><FONT size=2 face=Arial> for me, an object can</FONT><FONT size=2
face=Arial> be open in state and behavior (change in</FONT></DIV>
<DIV><FONT size=2 face=Arial> an unpredictable way)</FONT><FONT size=2
face=Arial> and still be "that object".</FONT></DIV>
<DIV><FONT size=2 face=Arial>Returning to your question about identity,
imho it is "something" in the</FONT></DIV>
<DIV><FONT size=2 face=Arial> observer, that reflect on a context
through time (here the</FONT></DIV>
<DIV><FONT size=2 face=Arial> virtue of the object-subject relation).
The object</FONT></DIV>
<DIV><FONT size=2 face=Arial> preserve the identity in the context
known to that</FONT></DIV>
<DIV><FONT size=2 face=Arial> observer (under a pov)</FONT></DIV>
<DIV><FONT size=2 face=Arial>The observer name the object (acording to
convenience/role in</FONT></DIV>
<DIV><FONT size=2 face=Arial> the "understanding"/control of the
context).</FONT></DIV>
<DIV><FONT size=2 face=Arial>Using a number for the name is primitive but can be
understood</FONT></DIV>
<DIV><FONT size=2 face=Arial> as</FONT><FONT size=2 face=Arial> a
valid name.</FONT></DIV>
<DIV><FONT size=2 face=Arial>In short, the ID is a name that is defined by the
observer when</FONT></DIV>
<DIV><FONT size=2 face=Arial> it is detected a presistence in time of
something taking a</FONT></DIV>
<DIV><FONT size=2 face=Arial> role (a model of the observer is the place
to implement it).</FONT></DIV>
<DIV><FONT size=2 face=Arial>No need to have an unique ID for each object,
because the</FONT></DIV>
<DIV><FONT size=2 face=Arial> universal pov it asumes is a
gravitator(innocent) and hide</FONT></DIV>
<DIV><FONT size=2 face=Arial> diversity of observers,</FONT><FONT size=2
face=Arial> the same way as an object realty</FONT></DIV>
<DIV><FONT size=2 face=Arial> is hidden if one assumes a</FONT><FONT size=2
face=Arial> system is defined by one source code.</FONT></DIV>
<DIV><FONT size=2 face=Arial>cheers,</FONT></DIV>
<DIV><FONT size=2 face=Arial>Ale.</FONT></DIV>
<DIV><FONT size=2 face=Arial> </FONT></DIV>
<DIV><FONT size=2 face=Arial></FONT> </DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black"><B>From:</B>
<A title=trygver@ifi.uio.no href="mailto:trygver@ifi.uio.no">Trygve
Reenskaug</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=squeak-dev@lists.squeakfoundation.org
href="mailto:squeak-dev@lists.squeakfoundation.org">The general-purpose Squeak
developers list</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, August 22, 2009 7:39
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [squeak-dev] Re: Newbie
Question (about OOPs, maybe) (sorry)</DIV>
<DIV><BR></DIV>Hi All,<BR>IMO, every object has three essential properties:
Identity, State, and Behavior. In Smalltalk, State and Behavior are defined by
the object's flattened class hierarchy. The Object ID is not explicitly
available. I have am using 'asOop', hoping I get a unique value. But I
realize that I am skating on thin ice because its comment confuses me with
implementation details. It doesn't say what it means by 'pointer', so there is
still hope:<BR><BR><I>Object>>asOop<BR> "Primitive.
Answer a SmallInteger whose value is half of the receiver's
<BR> object pointer (interpreting object pointers as 16-bit
signed
quantities)..."</I><BR><BR><I>ProtoObject>>identityHash<BR>
"Answer a SmallInteger whose value is related to the receiver's
identity..."<BR></I>This is pretty vague, but the term 'Hash' indicates that
many objects can share the same value. So it is clearly cannot be used as the
objectID.<BR><BR>The Morph>>printOn: implementation is less than ideal
because it should apply to all objects, not only Morphs. Also, it should use
'asOop' rather than 'identityHash' to let us hope for uniqueness.<BR><BR>In
short:<BR>
<UL>
<LI>Smalltalk claims to be object oriented and I regard it as a serious flaw
that the object ID is not explicitly visible.
<LI>We probably need a 64-bit VM to represent it properly, e.g., using the
standardized definition of OID, but a value that is guaranteed to be unique
within the current set of objects would be acceptable..
<LI>I regard it as a bug that Object>>printOn: does not present some
kind of object ID. </LI></UL>Cheers<BR>--Trygve<BR><BR><BR>On 2009.08.20
06:37, K. K. Subramaniam wrote:
<BLOCKQUOTE cite=mid:200908201007.18504.subbukk@gmail.com type="cite"><PRE wrap="">On Wednesday 19 Aug 2009 11:07:29 am Ronald Spengler wrote:
</PRE>
<BLOCKQUOTE type="cite"><PRE wrap="">Ah, so the GC in the VM swizzles the pointers out from under you.
<A class=moz-txt-link-freetext href="http://lists.squeakfoundation.org/pipermail/squeak-dev/1999-June/006170.htm">http://lists.squeakfoundation.org/pipermail/squeak-dev/1999-June/006170.htm</A>
l
</PRE></BLOCKQUOTE><PRE wrap=""><!---->This is the classic dilemma between name as an identifier and name as a
locator. The word "pointer" connotes the latter but gets used widely in the
former sense in Smalltalk code. Object Identifier (oid) is unambiguous but
doesn't sound half as cool as oop ;-).
Subbu
</PRE></BLOCKQUOTE><BR>
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<P class=MsoNormal><SPAN class=SpellE><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"
lang=EN-GB>Trygve</SPAN></SPAN><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt" lang=EN-GB>
Reenskaug<SPAN> </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
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<P class=MsoNormal><SPAN class=SpellE><SPAN class=GramE><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt"
lang=EN-GB>Morgedalsvn</SPAN></SPAN></SPAN><SPAN class=GramE><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt" lang=EN-GB>.</SPAN></SPAN><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt" lang=EN-GB> 5A
<SPAN> </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><SPAN style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">N-0378
Oslo<SPAN>
</SPAN>Tel: (+47) 22 49 57 27<O:P></O:P></SPAN></P>
<P class=MsoNormal><SPAN class=SpellE><SPAN
style="FONT-FAMILY: Arial; FONT-SIZE: 10pt">Norway</SPAN></SPAN><SPAN
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