95 lines
4.7 KiB
HTML
95 lines
4.7 KiB
HTML
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<!-- Common Lisp HyperSpec (TM), version 7.0 generated by Kent M. Pitman on Mon, 11-Apr-2005 2:31am EDT -->
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<HTML>
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<HEAD>
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<TITLE>CLHS: Function SET</TITLE>
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<H1><A REV=MADE HREF="http://www.lispworks.com/"><IMG WIDTH=80 HEIGHT=65 ALT="[LISPWORKS]" SRC="../Graphics/LWSmall.gif" ALIGN=Bottom></A><A REL=TOP HREF="../Front/index.htm"><IMG WIDTH=237 HEIGHT=65 ALT="[Common Lisp HyperSpec (TM)]" SRC="../Graphics/CLHS_Sm.gif" ALIGN=Bottom></A> <A REL=PREV HREF="f_makunb.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="c_symbol.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="e_unbo_1.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<HR>
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<A NAME="set"><I>Function</I> <B>SET</B></A> <P>
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<P><B>Syntax:</B><P>
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<P>
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<B>set</B> <I>symbol value</I> => <I>value</I><P>
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<P>
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<P><B>Arguments and Values:</B><P>
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<P>
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<I>symbol</I>---a <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A>. <P>
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<I>value</I>---an <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>object</I></A>. <P>
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<P><B>Description:</B><P>
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<P>
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<A REL=DEFINITION HREF="#set"><B>set</B></A> changes the contents of the <A REL=DEFINITION HREF="26_glo_v.htm#value_cell"><I>value cell</I></A> of <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> to the given <A REL=DEFINITION HREF="26_glo_v.htm#value"><I>value</I></A>. <P>
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<PRE>
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(set symbol value) == (setf (symbol-value symbol) value)
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</PRE>
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</TT> <P>
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<P><B>Examples:</B><P>
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<P>
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<PRE>
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(setf (symbol-value 'n) 1) => 1
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(set 'n 2) => 2
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(symbol-value 'n) => 2
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(let ((n 3))
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(declare (special n))
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(setq n (+ n 1))
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(setf (symbol-value 'n) (* n 10))
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(set 'n (+ (symbol-value 'n) n))
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n) => 80
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n => 2
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(let ((n 3))
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(setq n (+ n 1))
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(setf (symbol-value 'n) (* n 10))
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(set 'n (+ (symbol-value 'n) n))
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n) => 4
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n => 44
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(defvar *n* 2)
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(let ((*n* 3))
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(setq *n* (+ *n* 1))
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(setf (symbol-value '*n*) (* *n* 10))
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(set '*n* (+ (symbol-value '*n*) *n*))
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*n*) => 80
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*n* => 2
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(defvar *even-count* 0) => *EVEN-COUNT*
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(defvar *odd-count* 0) => *ODD-COUNT*
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(defun tally-list (list)
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(dolist (element list)
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(set (if (evenp element) '*even-count* '*odd-count*)
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(+ element (if (evenp element) *even-count* *odd-count*)))))
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(tally-list '(1 9 4 3 2 7)) => NIL
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*even-count* => 6
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*odd-count* => 20
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</PRE>
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</TT> <P>
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<P><B>Side Effects:</B><P>
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<P>
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The <A REL=DEFINITION HREF="26_glo_v.htm#value"><I>value</I></A> of <I>symbol</I> is changed. <P>
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<P><B>Affected By:</B> None.
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<P>
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<P><B>Exceptional Situations:</B> None.
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<P>
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<P><B>See Also:</B><P>
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<P>
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<A REL=DEFINITION HREF="s_setq.htm#setq"><B>setq</B></A>, <A REL=DEFINITION HREF="s_progv.htm#progv"><B>progv</B></A>, <A REL=DEFINITION HREF="f_symb_5.htm#symbol-value"><B>symbol-value</B></A> <P>
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<P><B>Notes:</B><P>
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<P>
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The function <A REL=DEFINITION HREF="#set"><B>set</B></A> is deprecated. <P>
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<A REL=DEFINITION HREF="#set"><B>set</B></A> cannot change the value of a <A REL=DEFINITION HREF="26_glo_l.htm#lexical_variable"><I>lexical variable</I></A>. <P>
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<P><HR>The following <A REL=META HREF="../Front/X3J13Iss.htm">X3J13 cleanup issue</A>, <I>not part of the specification</I>, applies to this section:<P><UL><LI> <A REL=CHILD HREF="../Issues/iss013.htm">ARGUMENTS-UNDERSPECIFIED:SPECIFY</A><P></UL><HR>
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<A REL=NAVIGATOR HREF="../Front/StartPts.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Starting Points]" SRC="../Graphics/StartPts.gif" ALIGN=Bottom></A><A REL=TOC HREF="../Front/Contents.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Contents]" SRC="../Graphics/Contents.gif" ALIGN=Bottom></A><A REL=INDEX HREF="../Front/X_Master.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Index]" SRC="../Graphics/Index.gif" ALIGN=Bottom></A><A REL=INDEX HREF="../Front/X_Symbol.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Symbols]" SRC="../Graphics/Symbols.gif" ALIGN=Bottom></A><A REL=GLOSSARY HREF="../Body/26_a.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Glossary]" SRC="../Graphics/Glossary.gif" ALIGN=Bottom></A><A HREF="../Front/X3J13Iss.htm"><IMG WIDTH=80 HEIGHT=40 ALT="[Issues]" SRC="../Graphics/Issues.gif" ALIGN=Bottom></A><BR>
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<A REL=COPYRIGHT HREF="../Front/Help.htm#Legal"><I>Copyright 1996-2005, LispWorks Ltd. All rights reserved.</I></A><P>
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