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<TITLE>CLHS: Issue CLASS-OBJECT-SPECIALIZER Writeup</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="../Issues/iss046_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="../Issues/iss047.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="../Issues/iss048_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>Issue CLASS-OBJECT-SPECIALIZER Writeup</H2>
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<PRE><B>Issue:</B> <A HREF="iss047.htm">CLASS-OBJECT-SPECIALIZER</A><P>
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<B>References:</B> Draft 8.81, p.4-15<P>
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Draft 8.81, Glossary<P>
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88-002R<P>
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<B>Category:</B> CHANGE<P>
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<B>Edit history:</B> Version 1, 28-Mar-91, Kim Barrett<P>
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<B>Status:</B> Proposal AFFIRM was approved at the 3/91 meeting<P>
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<P>
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<B>Problem description:<P>
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</B><P>
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It was recently noted that the 8.81 draft defines parameter specializer names<P>
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to include <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> objects. This inclusion seems to be without basis in<P>
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decisions made by X3J13, and the editor believes it to be an editorial error.<P>
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<P>
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However, there has been previous discussion of exactly this question on the<P>
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clos mailing list, in which the general consensus seemed to be that <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A><P>
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objects should be permitted as parameter specializer names.<P>
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<P>
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<B>Proposal (CLASS-OBJECT-SPECIALIZER:AFFIRM):<P>
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</B><P>
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Affirm the wording in the 8.81 draft on page 4-15, which states that a <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A><P>
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object may be used as a parameter specializer name.<P>
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<P>
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<B>Examples:<P>
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</B><P>
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(<A REL=DEFINITION HREF="../Body/m_defcla.htm#defclass"><B>defclass</B></A> foo-class () ())<P>
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(<A REL=DEFINITION HREF="../Body/m_defmet.htm#defmethod"><B>defmethod</B></A> foo-method ((x #.(<A REL=DEFINITION HREF="../Body/f_find_c.htm#find-class"><B>find-class</B></A> foo-class))) x)<P>
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<P>
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<B>Rationale:<P>
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</B><P>
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Not affirming the draft's wording would make parameter specializer names<P>
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inconsistent with other parts of the language, since the use of <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> objects<P>
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and <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> names are generally interchangeable when used as type specifiers.<P>
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<P>
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The draft already says this.<P>
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<P>
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<B>Current Practice:<P>
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</B><P>
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Lucid 4.0 and Chestnut's Lisp to C translator support this.<P>
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<P>
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Several other implementations probably also support this.<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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Likely 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 is an upwardly compatible change.<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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Some applications may already depend on this. In the mail discussion of this<P>
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question it was mentioned that CLIM may be using <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> objects as parameter<P>
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specializer names.<P>
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<P>
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<B>Performance impact:<P>
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</B><P>
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None.<P>
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<P>
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<B>Editorial impact:<P>
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</B><P>
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None if accepted, since the draft already contains the necessary words.<P>
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<P>
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<B>Esthetics:<P>
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</B><P>
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Avoiding inconsistancy regarding the distinction between <A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> objects and<P>
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<A REL=DEFINITION HREF="../Body/t_class.htm#class"><B>class</B></A> names when used as type specifiers is more esthetic.<P>
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<P>
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<B>Discussion:<P>
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</B><P>
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</PRE>
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