42 lines
2.2 KiB
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42 lines
2.2 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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<TITLE>29.3.8. Restart Functions</TITLE>
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<meta name="description" value=" Restart Functions">
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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=tex2html5731 HREF="node324.html"><IMG ALIGN=BOTTOM ALT="next" SRC="icons/next_motif.gif"></A> <A NAME=tex2html5729 HREF="node315.html"><IMG ALIGN=BOTTOM ALT="up" SRC="icons/up_motif.gif"></A> <A NAME=tex2html5723 HREF="node322.html"><IMG ALIGN=BOTTOM ALT="previous" SRC="icons/previous_motif.gif"></A> <A NAME=tex2html5733 HREF="node1.html"><IMG ALIGN=BOTTOM ALT="contents" SRC="icons/contents_motif.gif"></A> <A NAME=tex2html5734 HREF="index.html"><IMG ALIGN=BOTTOM ALT="index" SRC="icons/index_motif.gif"></A> <BR>
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<B> Next:</B> <A NAME=tex2html5732 HREF="node324.html"> Comparison of Restarts </A>
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<B>Up:</B> <A NAME=tex2html5730 HREF="node315.html"> Survey of Concepts</A>
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<B> Previous:</B> <A NAME=tex2html5724 HREF="node322.html"> Named Restarts</A>
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<HR> <P>
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<H2><A NAME=SECTION003338000000000000000>29.3.8. Restart Functions</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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For commonly used restarts, it is conventional to define a program interface
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that hides the use of <tt>invoke-restart</tt>. Such program interfaces to restarts
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are called <i>restart functions</i>.
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<P>
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The normal convention is for the function to share the name of the restart.
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The pre-defined functions <tt>abort</tt>, <tt>continue</tt>, <tt>muffle-warning</tt>, <tt>store-value</tt>, and
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<tt>use-value</tt> are restart functions. With <tt>use-value</tt> the above example of
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<tt>handler-bind</tt> could have been written more concisely as
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<P><pre>
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(handler-bind ((unbound-variable
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#'(lambda (c) ;Argument <tt>c</tt> is a condition
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(use-value (cell-error-name c)))))
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<i>body</i>)
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</pre><P>
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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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