43 lines
2.4 KiB
HTML
43 lines
2.4 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3O//DTD W3 HTML 2.0//EN">
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<!Converted with LaTeX2HTML 0.6.5 (Tue Nov 15 1994) by Nikos Drakos (nikos@cbl.leeds.ac.uk), CBLU, University of Leeds >
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<HEAD>
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<TITLE>28.1.10.1. Modifying the Structure of Instances</TITLE>
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<BODY>
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<meta name="description" value=" Modifying the Structure of Instances">
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<meta name="keywords" value="clm">
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<meta name="resource-type" value="document">
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<meta name="distribution" value="global">
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<P>
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<b>Common Lisp the Language, 2nd Edition</b>
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<BR> <HR><A NAME=tex2html5421 HREF="node302.html"><IMG ALIGN=BOTTOM ALT="next" SRC="icons/next_motif.gif"></A> <A NAME=tex2html5419 HREF="node300.html"><IMG ALIGN=BOTTOM ALT="up" SRC="icons/up_motif.gif"></A> <A NAME=tex2html5413 HREF="node300.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="icons/previous_motif.gif"></A> <A NAME=tex2html5423 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="icons/contents_motif.gif"></A> <A NAME=tex2html5424 HREF="index.html"><IMG ALIGN=BOTTOM ALT="index" SRC="icons/index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html5422 HREF="node302.html"> Initializing Newly Added </A>
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<B>Up:</B> <A NAME=tex2html5420 HREF="node300.html"> Redefining Classes</A>
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<B> Previous:</B> <A NAME=tex2html5414 HREF="node300.html"> Redefining Classes</A>
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<HR> <P>
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<H3><A NAME=SECTION0032110100000000000000>28.1.10.1. Modifying the Structure of Instances</A></H3>
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<P>
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<img align=bottom alt="change_begin" src="gif/change_begin.gif"><br>
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The first step modifies the structure of instances of the redefined
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class to conform to its new class definition. Local slots specified
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by the new class definition that are not specified as either local or
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shared by the old class are added, and slots not specified as either
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local or shared by the new class definition that are specified as
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local by the old class are discarded. The names of these added and discarded
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slots are passed as arguments to <tt>update-instance-for-redefined-class</tt>
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as described in the next section.
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<P>
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The values of local slots specified by both the new and old classes
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are retained. If such a local slot was unbound, it remains unbound.
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<P>
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The value of a slot that is specified as shared in the old class and
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as local in the new class is retained. If such a shared slot was
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unbound, the local slot will be unbound.
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<br><img align=bottom alt="change_end" src="gif/change_end.gif">
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<P>
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<HR>
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<P><ADDRESS>
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AI.Repository@cs.cmu.edu
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</ADDRESS>
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</BODY>
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