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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/iss192_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="../Issues/iss193.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="../Issues/iss194_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>Issue IGNORE-USE-TERMINOLOGY Writeup</H2>
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<PRE><B>Forum:</B> Public Review<P>
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<B>Issue:</B> <A HREF="iss193.htm">IGNORE-USE-TERMINOLOGY</A><P>
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<B>References:</B> Barrett's public review comment #30<P>
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<A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A>, <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A><P>
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<B>Category:</B> CLARIFICATION<P>
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<B>Edit history:</B> 21 Dec 1992, Version 1 by Loosemore<P>
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<B>Status:</B> Proposal VALUE-ONLY passed (7+1)-2 on letter ballot 93-302<P>
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<P>
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<P>
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<B>Problem description:<P>
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</B><P>
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In the description of the <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> declaration, there are several<P>
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occurances of "use", "used", "referred to", and "referenced", which<P>
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are not well specified. The question is, what constitutes a use of a<P>
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binding. Are only references for value considered to be "uses~, or<P>
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should references as a place to modify also be considered "uses"?<P>
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Implementations differ on this question, making it very difficult to<P>
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use the <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> declaration in portable code.<P>
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<P>
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There are two proposals, VALUE-ONLY and VALUE-AND-ASSIGNMENT.<P>
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<P>
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<P>
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<B>Proposal (IGNORE-USE-TERMINOLOGY:VALUE-ONLY):<P>
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</B><P>
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Change the description of the <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> and <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A> declarations to<P>
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use the glossary term "reference" throughout.<P>
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<P>
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Clarify that, for the purposes of <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> and <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A>, a "reference"<P>
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includes only references for value. <P>
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<P>
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<P>
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<B>Proposal (IGNORE-USE-TERMINOLOGY:VALUE-AND-ASSIGNMENT):<P>
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</B> <P>
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Change the description of the <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> and <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A> declarations to<P>
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use the glossary term "reference" throughout.<P>
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<P>
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Clarify that, for the purposes of <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> and <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A>, a "reference"<P>
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includes both references for value and variable assignments.<P>
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<P>
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<P>
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<B>Rationale:<P>
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</B><P>
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Either one of these proposals would address the problem.<P>
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<P>
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<P>
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<B>Current practice:<P>
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</B><P>
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Unknown.<P>
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<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 small.<P>
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<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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Probably small.<P>
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<P>
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<P>
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<B>Aesthetics:<P>
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</B><P>
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Specifying this behavior is more aesthetic than leaving it unspecified.<P>
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<P>
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<P>
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<B>Editorial impact:<P>
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</B><P>
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The changes are confined to the dictionary entry for <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> and<P>
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<A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A>.<P>
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<P>
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<P>
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<B>Discussion:<P>
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</B><P>
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Barrett has indicated he prefers proposal VALUE-ONLY, but Loosemore<P>
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thinks that having variables that can be assigned to but not<P>
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referenced are of questionable utility.<P>
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<P>
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While researching this issue, Loosemore noted that the provision<P>
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about the behavior of <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignore"><B>IGNORE</B></A> (and presumably <A REL=DEFINITION HREF="../Body/d_ignore.htm#ignorable"><B>IGNORABLE</B></A>) from issue<P>
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<A HREF="iss228.htm">MACRO-DECLARATIONS</A> had not been incorporated into draft 12.24. Can<P>
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we give the editor authority to remedy this? <P>
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</PRE>
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