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119 lines
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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="../Issues/iss340_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="../Issues/iss341.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="../Issues/iss342_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>Issue SYMBOL-PRINT-ESCAPE-BEHAVIOR Writeup</H2>
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<PRE><B>Issue:</B> <A HREF="iss341.htm">SYMBOL-PRINT-ESCAPE-BEHAVIOR</A><P>
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<B>Forum:</B> X3J13 Letter Ballot<P>
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<B>References:</B> <A REL=DEFINITION HREF="../Body/v_pr_esc.htm#STprint-escapeST"><B>*PRINT-ESCAPE*</B></A> (X3J13/92-102, p22-4)<P>
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Public review comment Moon-1<P>
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Public review comment Loosemore-17<P>
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Public review comment Pitman-9<P>
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<B>Category:</B> CLARIFICATION<P>
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<B>Edit history:</B> 21-Jun-93, Version 1 by Steele (based on text by Loosemore)<P>
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<B>Status:</B> Proposal CLARIFY passed 10-1 on letter ballot 93-304.<P>
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<P>
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<B>Problem Description:<P>
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</B><P>
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The description of how symbols are printed when <A REL=DEFINITION HREF="../Body/v_pr_esc.htm#STprint-escapeST"><B>*PRINT-ESCAPE*</B></A> is<P>
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true is too vague. Three PR commentors remarked on this.<P>
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<P>
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<B>Proposal (SYMBOL-PRINT-ESCAPE-BEHAVIOR:CLARIFY):<P>
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</B><P>
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Replace the text:<P>
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<P>
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\term{Backslashes} and \term{vertical-bars} are included as required. <P>
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The \term{current output base} at the time of printing might be relevant.<P>
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For example, if \thevalueof{*print-base*} were \f{16} <P>
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when printing the symbol \f{face}, it would have to be printed as<P>
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\f{\\FACE} or \f{\\Face} or \f{|FACE|}, <P>
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because the token \f{face} would be read as a hexadecimal<P>
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number (decimal value 64206) if \thevalueof{*read-base*} were \f{16}.<P>
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<P>
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with:<P>
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<P>
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When printing a \term{symbol}, the printer inserts enough <P>
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\term{single escape} and/or \term{multiple escape}<P>
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characters (\term{backslashes} and/or \term{vertical-bars}) so that if<P>
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\funref{read} were called with the same \varref{*readtable*} and<P>
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with \varref{*read-base*} bound to the \term{current output base}, it<P>
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would return the same \term{symbol} (if it is not <P>
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\term{apparently uninterned}) or an \term{uninterned} \term{symbol}<P>
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with the same \term{print name} (otherwise).<P>
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<P>
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For example, if \thevalueof{*print-base*} were \f{16} <P>
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when printing the symbol \f{face}, it would have to be printed as<P>
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\f{\\FACE} or \f{\\Face} or \f{|FACE|}, <P>
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because the token \f{face} would be read as a hexadecimal<P>
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number (decimal value 64206) if \thevalueof{*read-base*} were \f{16}.<P>
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<P>
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See \varref{*print-readably*} for additional restrictions concerning<P>
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characters with nonstandard \term{syntax types} in the <P>
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\term{current readtable}.<P>
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<P>
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<B>Test Case:<P>
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</B><P>
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Not provided.<P>
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<P>
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<B>Rationale:<P>
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</B><P>
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Explain more fully what is meant by "as required".<P>
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<P>
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<B>Current Practice:<P>
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</B><P>
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Not provided.<P>
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<P>
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<B>Cost to Implementors:<P>
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</B><P>
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Probably relatively small.<P>
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<P>
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<B>Cost to Users:<P>
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</B><P>
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None. This change doesn't affect anything already guaranteed to the user.<P>
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<P>
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<B>Cost of Non-Adoption:<P>
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</B><P>
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Vagueness in the language specification.<P>
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<P>
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<B>Benefits:<P>
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</B><P>
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Better program portability.<P>
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<P>
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<B>Editorial Impact:<P>
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</B><P>
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Small. A small, localized edit.<P>
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<P>
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<B>Aesthetics:<P>
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</B><P>
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Mostly neutral.<P>
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<P>
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<B>Discussion:<P>
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</B> <P>
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This addresses comments Moon #1, Loosemore #17, and Pitman #9.<P>
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<P>
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</PRE>
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