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>nth-value | Common Lisp Nova Spec</TITLE
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><B
>nth-value</B
></TD
><TD ALIGN="RIGHT" VALIGN="BASELINE" WIDTH="0" NOWRAP="NOWRAP" CLASS="ftype"
><I
>Macro</I
></TD
></TR
></TABLE
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><DT
><B
>Syntax</B
></DT
><DD
><P CLASS="j"
><B
>nth-value</B
> <SPAN CLASS="cmssi"
>n</SPAN
> <SPAN CLASS="cmssi"
>form</SPAN
> <SPAN CLASS="arrow"
>&#8594;</SPAN
> <SPAN CLASS="cmssi"
>object</SPAN
></P
></DD
><DT
><B
>Arguments and Values</B
></DT
><DD
><P CLASS="j"
><VAR CLASS="param"
>n</VAR
> &#8212; a non-negative <A HREF="26_1_Glossary.html#integer"
><EM CLASS="term"
>integer</EM
></A
>; evaluated. </P
><P CLASS="j"
><VAR CLASS="param"
>form</VAR
> &#8212; a <A HREF="26_1_Glossary.html#form"
><EM CLASS="term"
>form</EM
></A
>; evaluated as described below. </P
><P CLASS="j"
><VAR CLASS="param"
>object</VAR
> &#8212; an <A HREF="26_1_Glossary.html#object"
><EM CLASS="term"
>object</EM
></A
>.</P
></DD
><DT
><B
>Description</B
></DT
><DD
><P CLASS="j"
>Evaluates <VAR CLASS="param"
>n</VAR
> and then <VAR CLASS="param"
>form</VAR
>, returning as its only value the <VAR CLASS="param"
>n</VAR
>th value <A HREF="26_1_Glossary.html#yield"
><EM CLASS="term"
>yielded</EM
></A
> by <VAR CLASS="param"
>form</VAR
>, or <SPAN CLASS="misc"
><B
>nil</B
></SPAN
> if <VAR CLASS="param"
>n</VAR
> is greater than or equal to the number of <A HREF="26_1_Glossary.html#value"
><EM CLASS="term"
>values</EM
></A
> returned by <VAR CLASS="param"
>form</VAR
>. (The first returned value is numbered <CODE CLASS="f"
>0</CODE
>.)</P
></DD
><DT
><B
>Examples</B
></DT
><DD
><PRE CLASS="screen"
> (nth-value 0 (values 'a 'b)) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> A
(nth-value 1 (values 'a 'b)) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> B
(nth-value 2 (values 'a 'b)) <SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> NIL
(let* ((x 83927472397238947423879243432432432)
(y 32423489732)
(a (nth-value 1 (floor x y)))
(b (mod x y)))
(values a b (= a b)))
<SPAN CLASS="cmsy"
><SPAN CLASS="arrow"
>&#8594;</SPAN
></SPAN
> 3332987528, 3332987528, <A HREF="26_1_Glossary.html#true"
><EM CLASS="term"
>true</EM
></A
></PRE
></DD
><DT
><B
>See Also</B
></DT
><DD
><P CLASS="j"
><A HREF="f_multiple-value-list.html" CLASS="macref"
><B
>multiple-value-list</B
></A
>, <A HREF="f_nth.html" CLASS="funref"
><B
>nth</B
></A
></P
></DD
><DT
><B
>Notes</B
></DT
><DD
><P CLASS="j"
>Operationally, the following relationship is true, although <A HREF="f_nth-value.html" CLASS="macref"
><B
>nth-value</B
></A
> might be more efficient in some <A HREF="26_1_Glossary.html#implementation"
><EM CLASS="term"
>implementations</EM
></A
> because, for example, some <A HREF="26_1_Glossary.html#cons"
><EM CLASS="term"
>consing</EM
></A
> might be avoided.</P
><PRE CLASS="screen"
>(nth-value <VAR CLASS="param"
>n</VAR
> <VAR CLASS="param"
>form</VAR
>) <SPAN CLASS="cmsy"
><SPAN STYLE="font-size:16px;vertical-align:-2px"
>&#8801;</SPAN
></SPAN
> (nth <VAR CLASS="param"
>n</VAR
> (multiple-value-list <VAR CLASS="param"
>form</VAR
>))</PRE
></DD
></DL
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