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2.7 KiB
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47 lines
2.7 KiB
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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>28.1.7. Method Selection and Combination</TITLE>
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<BODY>
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<meta name="description" value=" Method Selection and Combination">
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<meta name="keywords" value="clm">
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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=tex2html5193 HREF="node284.html"><IMG ALIGN=BOTTOM ALT="next" SRC="icons/next_motif.gif"></A> <A NAME=tex2html5191 HREF="node261.html"><IMG ALIGN=BOTTOM ALT="up" SRC="icons/up_motif.gif"></A> <A NAME=tex2html5185 HREF="node282.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="icons/previous_motif.gif"></A> <A NAME=tex2html5195 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="icons/contents_motif.gif"></A> <A NAME=tex2html5196 HREF="index.html"><IMG ALIGN=BOTTOM ALT="index" SRC="icons/index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html5194 HREF="node284.html"> Determining the Effective </A>
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<B>Up:</B> <A NAME=tex2html5192 HREF="node261.html"> Programmer Interface Concepts</A>
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<B> Previous:</B> <A NAME=tex2html5186 HREF="node282.html"> Keyword Arguments in </A>
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<HR> <P>
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<H2><A NAME=SECTION003217000000000000000>28.1.7. Method Selection and Combination</A></H2>
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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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<A NAME=MethodSelectionandCombinationSECTION>When</A>
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a generic function is called with particular arguments, it must
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determine the code to execute. This code is called the <i>effective
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method</i> for those arguments. The effective method is a <i>combination</i> of the applicable methods in the generic function. A
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combination of methods is a Lisp expression that contains calls to some or
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all of the methods. If a generic function is
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called and no methods apply, the generic function
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<tt>no-applicable-method</tt> is invoked.
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<P>
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When the effective method has been determined, it is invoked with the same
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arguments that were passed to the generic function. Whatever values it
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returns are returned as the values of the generic function.
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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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<UL>
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<LI> <A NAME=tex2html5197 HREF="node284.html#SECTION003217100000000000000"> Determining the Effective Method</A>
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<LI> <A NAME=tex2html5198 HREF="node285.html#SECTION003217200000000000000"> Standard Method Combination</A>
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<LI> <A NAME=tex2html5199 HREF="node286.html#SECTION003217300000000000000"> Declarative Method Combination</A>
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<LI> <A NAME=tex2html5200 HREF="node287.html#SECTION003217400000000000000"> Built-in Method Combination Types</A>
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</UL>
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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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