34 lines
5.4 KiB
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34 lines
5.4 KiB
HTML
<!-- 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 2.4.8.1</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_dh.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_dhb.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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2.4.8.1 Sharpsign Backslash</H2> <P>
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<B>Syntax:</B> <TT>#\<<</TT><I>x</I><TT>>></TT> <P>
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When the <A REL=DEFINITION HREF="26_glo_t.htm#token"><I>token</I></A> <I>x</I> is a single <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> long, this parses as the literal <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> <I>char</I>. <A REL=DEFINITION HREF="26_glo_u.htm#uppercase"><I>Uppercase</I></A> and <A REL=DEFINITION HREF="26_glo_l.htm#lowercase"><I>lowercase</I></A> letters are distinguished after <TT>#\</TT>; <TT>#\A</TT> and <TT>#\a</TT> denote different <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>objects</I></A>. Any single <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> works after <TT>#\</TT>, even those that are normally special to <A REL=DEFINITION HREF="f_rd_rd.htm#read"><B>read</B></A>, such as <A REL=DEFINITION HREF="26_glo_l.htm#left-parenthesis"><I>left-parenthesis</I></A> and <A REL=DEFINITION HREF="26_glo_r.htm#right-parenthesis"><I>right-parenthesis</I></A>. <P>
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In the single <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> case, the <I>x</I> must be followed by a non-constituent <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A>. After <TT>#\</TT> is read, the reader backs up over the <A REL=DEFINITION HREF="26_glo_s.htm#slash"><I>slash</I></A> and then reads a <A REL=DEFINITION HREF="26_glo_t.htm#token"><I>token</I></A>, treating the initial <A REL=DEFINITION HREF="26_glo_s.htm#slash"><I>slash</I></A> as a <A REL=DEFINITION HREF="26_glo_s.htm#single_escape"><I>single escape</I></A> <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> (whether it really is or not in the <A REL=DEFINITION HREF="26_glo_c.htm#current_readtable"><I>current readtable</I></A>). <P>
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When the <A REL=DEFINITION HREF="26_glo_t.htm#token"><I>token</I></A> <I>x</I> is more than one <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> long, the <I>x</I> must have the syntax of a <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> with no embedded <A REL=DEFINITION HREF="26_glo_p.htm#package_marker"><I>package markers</I></A>. In this case, the <A REL=DEFINITION HREF="26_glo_s.htm#sharpsign"><I>sharpsign</I></A> <A REL=DEFINITION HREF="26_glo_b.htm#backslash"><I>backslash</I></A> notation parses as the <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> whose <A REL=DEFINITION HREF="26_glo_n.htm#name"><I>name</I></A> is <TT>(string-upcase </TT><I>x</I><TT>)</TT>; see <A REL=CHILD HREF="13_ag.htm">Section 13.1.7 (Character Names)</A>. <P>
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<P>
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For information about how the <A REL=DEFINITION HREF="26_glo_l.htm#lisp_printer"><I>Lisp printer</I></A> prints <A REL=DEFINITION HREF="26_glo_c.htm#character"><I>character</I></A> <A REL=DEFINITION HREF="26_glo_o.htm#object"><I>objects</I></A>, see <A REL=CHILD HREF="22_acb.htm">Section 22.1.3.2 (Printing Characters)</A>. <P>
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<P><HR>The following <A REL=META HREF="../Front/X3J13Iss.htm">X3J13 cleanup issues</A>, <I>not part of the specification</I>, apply to this section:<P><UL><LI> <A REL=CHILD HREF="../Issues/iss025.htm">CHARACTER-LOOSE-ENDS:FIX</A><LI> <A REL=CHILD HREF="../Issues/iss027.htm">CHARACTER-PROPOSAL:2-1-1</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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