34 lines
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34 lines
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<TITLE>CLHS: Section 5.1.2.3</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="05_abb.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="05_ab.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="05_abd.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>
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5.1.2.3 VALUES Forms as Places</H2> <P>
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A <A REL=DEFINITION HREF="f_values.htm#values"><B>values</B></A> <A REL=DEFINITION HREF="26_glo_f.htm#form"><I>form</I></A> can be used as a <A REL=DEFINITION HREF="26_glo_p.htm#place"><I>place</I></A>, provided that each of its <A REL=DEFINITION HREF="26_glo_s.htm#subform"><I>subforms</I></A> is also a <A REL=DEFINITION HREF="26_glo_p.htm#place"><I>place</I></A> form. <P>
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A form such as <P>
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<TT>(setf (values </TT><I>place-1</I><TT> ...</TT><I>place-n</I><TT>) </TT><I>values-form</I><TT>)</TT> <P>
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does the following: <P>
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<P><DL><DT>1. The <A REL=DEFINITION HREF="26_glo_s.htm#subform"><I>subforms</I></A> of each nested <I>place</I> are evaluated in left-to-right order. <DD><DT>2. The <I>values-form</I> is evaluated, and the first store variable from each <I>place</I> is bound to its return values as if by <A REL=DEFINITION HREF="m_multip.htm#multiple-value-bind"><B>multiple-value-bind</B></A>. <DD><DT>3. If the <A REL=DEFINITION HREF="26_glo_s.htm#setf_expansion"><I>setf expansion</I></A> for any <I>place</I> involves more than one store variable, then the additional store variables are bound to <A REL=DEFINITION HREF="a_nil.htm#nil"><B>nil</B></A>. <DD><DT>4. The storing forms for each <I>place</I> are evaluated in left-to-right order. <P><DD></DL><P>
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The storing form in the <A REL=DEFINITION HREF="26_glo_s.htm#setf_expansion"><I>setf expansion</I></A> of <A REL=DEFINITION HREF="f_values.htm#values"><B>values</B></A> returns as <A REL=DEFINITION HREF="26_glo_m.htm#multiple_values"><I>multiple values</I></A>[2] the values of the store variables in step 2. That is, the number of values returned is the same as the number of <A REL=DEFINITION HREF="26_glo_p.htm#place"><I>place</I></A> forms. This may be more or fewer values than are produced by the <I>values-form</I>. <P>
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