46 lines
4.3 KiB
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46 lines
4.3 KiB
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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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<TITLE>CLHS: Section 2.4.8.3</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="02_dhb.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="02_dh.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="02_dhd.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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2.4.8.3 Sharpsign Left-Parenthesis</H2> <P>
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<TT>#(</TT> and <TT>)</TT> are used to notate a <A REL=DEFINITION HREF="26_glo_s.htm#simple_vector"><I>simple vector</I></A>. <P>
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If an unsigned decimal integer appears between the <TT>#</TT> and <TT>(</TT>, it specifies explicitly the length of the <A REL=DEFINITION HREF="26_glo_v.htm#vector"><I>vector</I></A>. The consequences are undefined if the number of <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>objects</I></A> specified before the closing <TT>)</TT> exceeds the unsigned decimal integer. If the number of <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>objects</I></A> supplied before the closing <TT>)</TT> is less than the unsigned decimal integer but greater than zero, the last <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>object</I></A> is used to fill all remaining elements of the <A REL=DEFINITION HREF="26_glo_v.htm#vector"><I>vector</I></A>. The consequences are undefined if the unsigned decimal integer is non-zero and number of <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>objects</I></A> supplied before the closing <TT>)</TT> is zero. For example, <P>
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<PRE>
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#(a b c c c c)
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#6(a b c c c c)
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#6(a b c)
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#6(a b c c)
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</PRE>
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</TT> <P>
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all mean the same thing: a <A REL=DEFINITION HREF="26_glo_v.htm#vector"><I>vector</I></A> of length <TT>6</TT> with <A REL=DEFINITION HREF="26_glo_e.htm#element"><I>elements</I></A> <TT>a</TT>, <TT>b</TT>, and four occurrences of <TT>c</TT>. Other examples follow: <P>
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<PRE>
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#(a b c) ;A vector of length 3
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#(2 3 5 7 11 13 17 19 23 29 31 37 41 43 47)
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;A vector containing the primes below 50
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#() ;An empty vector
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</PRE>
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</TT> The notation <TT>#()</TT> denotes an empty <A REL=DEFINITION HREF="26_glo_v.htm#vector"><I>vector</I></A>, as does <TT>#0()</TT>. <P>
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For information on how the <A REL=DEFINITION HREF="26_glo_l.htm#lisp_printer"><I>Lisp printer</I></A> prints <A REL=DEFINITION HREF="26_glo_v.htm#vector"><I>vectors</I></A>, see <A REL=CHILD HREF="22_acd.htm">Section 22.1.3.4 (Printing Strings)</A>, <A REL=CHILD HREF="22_acf.htm">Section 22.1.3.6 (Printing Bit Vectors)</A>, or <A REL=CHILD HREF="22_acg.htm">Section 22.1.3.7 (Printing Other Vectors)</A>. <P>
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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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