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<H2>Issue EVAL-WHEN-OBSOLETE-KEYWORDS Writeup</H2>
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<PRE><B>Forum:</B> Public Review<P>
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<B>Issue:</B> <A HREF="iss148.htm">EVAL-WHEN-OBSOLETE-KEYWORDS</A><P>
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<B>References:</B> Moon's public review comment #2 (X3J13/92-3202)<P>
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<A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A><P>
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Issue <A HREF="iss147.htm">EVAL-WHEN-NON-TOP-LEVEL</A><P>
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<B>Category:</B> CHANGE<P>
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<B>Edit history:</B> 20 Dec 1992, Version 1 by Loosemore<P>
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08 Jan 1993, Version 2 by Loosemore (comments from Moon)<P>
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12 Sept 1993, Version 3 by Loosemore (add second proposal)<P>
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<B>Status:</B> Proposal REMOVE-OLD-KEYWORDS failed 3-6-0, March 1993<P>
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Proposal X3J13-MARCH-1993 passed 6-1, March 1993<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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The language in draft 12.24 about the relationship between<P>
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the new <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A> keywords :EXECUTE, :COMPILE-TOPLEVEL, and<P>
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:LOAD-TOPLEVEL and the old, deprecated keywords <A REL=DEFINITION HREF="../Body/f_eval.htm#eval"><B>EVAL</B></A>, <A REL=DEFINITION HREF="../Body/f_cmp.htm#compile"><B>COMPILE</B></A>, and <P>
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<A REL=DEFINITION HREF="../Body/f_load.htm#load"><B>LOAD</B></A> is confusing. (For example, it's inconsistent about what<P>
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<A REL=DEFINITION HREF="../Body/f_eval.htm#eval"><B>EVAL</B></A> means when not at top level.) The compatibility argument<P>
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for retaining two sets of keywords with slightly different<P>
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meanings is outweighed by the resulting confusion.<P>
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<P>
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<P>
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<B>Proposal (EVAL-WHEN-OBSOLETE-KEYWORDS:REMOVE-OLD-KEYWORDS):<P>
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</B><P>
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Eliminate all mention of the old keywords <A REL=DEFINITION HREF="../Body/f_eval.htm#eval"><B>EVAL</B></A>, <A REL=DEFINITION HREF="../Body/f_cmp.htm#compile"><B>COMPILE</B></A>, and <A REL=DEFINITION HREF="../Body/f_load.htm#load"><B>LOAD</B></A><P>
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in connection with <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A>.<P>
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<P>
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<B>Proposal (EVAL-WHEN-OBSOLETE-KEYWORDS:X3J13-MARCH-1993):<P>
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</B><P>
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Generalize the use of the old keywords; define that <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>eval-when</B></A> always <P>
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treats <A REL=DEFINITION HREF="../Body/f_eval.htm#eval"><B>eval</B></A> the same as :execute, compile the same as :compile-toplevel,<P>
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and load the same as :load-toplevel.<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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Adopting this suggestion would shorten the specification and remove<P>
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an inconsistency. There are so many incompatibilities between<P>
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CLtL1, CLtL2, and the draft <A REL=DEFINITION HREF="../Body/07_ffb.htm#standard"><B>standard</B></A> that it's pointless to try to<P>
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allow for a modeless implementation that is simultaneously compatible<P>
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with all of them.<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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Moon says he's not aware of any implementations whose current releases<P>
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don't support the new keywords.<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; implementations could continue to support the old<P>
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keywords as an extension.<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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This is an incompatible change, but one that is easy to detect. A<P>
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good implementation should complain about unrecognized <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A><P>
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keywords, anyway.<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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Making the <A REL=DEFINITION HREF="../Body/07_ffb.htm#standard"><B>standard</B></A> simpler is a good thing.<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 dictionary entry for <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A> is the only place affected.<P>
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(The discussion of <A REL=DEFINITION HREF="../Body/s_eval_w.htm#eval-when"><B>EVAL-WHEN</B></A> in <A REL=DEFINITION HREF="../Body/s_the.htm#the"><B>the</B></A> concept section relating to<P>
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file compilation uses <A REL=DEFINITION HREF="../Body/s_the.htm#the"><B>the</B></A> new keywords exclusively.)<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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Moon says: <P>
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I like EVAL-WHEN-NON-TOP-LEVEL:REMOVE-OLD-KEYWORDS (version 1).<P>
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<P>
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Moon suggested (in his public review comment) that another way to <P>
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resolve this problem would be to define the behavior of the old <P>
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keywords to be exactly the same as that of the new keywords.<P>
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<P>
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<P>
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<P>
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<P>
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<P>
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<P>
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</PRE>
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