108 lines
6.3 KiB
HTML
108 lines
6.3 KiB
HTML
<!-- Common Lisp HyperSpec (TM), version 7.0 generated by Kent M. Pitman on Mon, 11-Apr-2005 2:31am EDT -->
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>CLHS: Issue SYMBOL-MACROLET-DECLARE Writeup</TITLE>
|
|
<LINK HREF="../Data/clhs.css" REL="stylesheet" TYPE="text/css" />
|
|
<META HTTP-EQUIV="Author" CONTENT="Kent M. Pitman">
|
|
<META HTTP-EQUIV="Organization" CONTENT="LispWorks Ltd.">
|
|
<LINK REL=TOP HREF="../Front/index.htm">
|
|
<LINK REL=COPYRIGHT HREF="../Front/Help.htm#Legal">
|
|
<LINK REL=DISCLAIMER HREF="../Front/Help.htm#Disclaimer">
|
|
<LINK REL=PREV HREF="../Issues/iss336_w.htm">
|
|
<LINK REL=UP HREF="../Issues/iss337.htm">
|
|
<LINK REL=NEXT HREF="../Issues/iss338_w.htm">
|
|
</HEAD>
|
|
<BODY>
|
|
<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/iss336_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="../Issues/iss337.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="../Issues/iss338_w.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
|
|
|
|
<HR>
|
|
|
|
|
|
|
|
<H2>Issue SYMBOL-MACROLET-DECLARE Writeup</H2>
|
|
|
|
<PRE><B>Issue:</B> <A HREF="iss337.htm">SYMBOL-MACROLET-DECLARE</A><P>
|
|
<P>
|
|
<B>References:</B> <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> (88-002R page 2-81)<P>
|
|
<A REL=DEFINITION HREF="../Body/m_w_acce.htm#with-accessors"><B>WITH-ACCESSORS</B></A> (88-002R page 2-88)<P>
|
|
<A REL=DEFINITION HREF="../Body/m_w_slts.htm#with-slots"><B>WITH-SLOTS</B></A> (88-002R page 2-92)<P>
|
|
<P>
|
|
Related Issues: <A HREF="iss338.htm">SYMBOL-MACROLET-SEMANTICS</A><P>
|
|
<A HREF="iss159_m.htm">FLET-DECLARATIONS</A> (passed)<P>
|
|
<P>
|
|
<B>Category:</B> ADDITION<P>
|
|
<P>
|
|
<B>Edit history:</B> Version 1, 12-Sep-88, Moon<P>
|
|
Version 2, 9-Dec-88, Masinter<P>
|
|
(add cross reference, discussion)<P>
|
|
<P>
|
|
<B>Problem description:<P>
|
|
</B><P>
|
|
It would be both natural and nice to be able to write<P>
|
|
<P>
|
|
(<A REL=DEFINITION HREF="../Body/m_w_slts.htm#with-slots"><B>with-slots</B></A> (rho theta) point<P>
|
|
(<A REL=DEFINITION HREF="../Body/s_declar.htm#declare"><B>declare</B></A> (<A REL=DEFINITION HREF="../Body/t_short_.htm#single-float"><B>single-float</B></A> rho theta))<P>
|
|
...computation...)<P>
|
|
<P>
|
|
<B>Proposal (SYMBOL-MACROLET-DECLARE:ALLOW):<P>
|
|
</B> <P>
|
|
Allow declarations at the head of the body of <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A>, and hence<P>
|
|
in <A REL=DEFINITION HREF="../Body/m_w_acce.htm#with-accessors"><B>WITH-ACCESSORS</B></A> and <A REL=DEFINITION HREF="../Body/m_w_slts.htm#with-slots"><B>WITH-SLOTS</B></A>. Exactly the same declarations are<P>
|
|
allowed as for <A REL=DEFINITION HREF="../Body/s_let_l.htm#let"><B>LET</B></A>, with one exception: <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> signals an error<P>
|
|
if a <A REL=DEFINITION HREF="../Body/d_specia.htm#special"><B>SPECIAL</B></A> declaration names one of the symbols being defined as a<P>
|
|
<A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>symbol-macrolet</B></A>. A type declaration of one of these symbols is equivalent<P>
|
|
to wrapping a <A REL=DEFINITION HREF="../Body/s_the.htm#the"><B>THE</B></A> expression around the expansion of that symbol.<P>
|
|
<P>
|
|
<B>Example:<P>
|
|
</B><P>
|
|
See problem description.<P>
|
|
<P>
|
|
<B>Rationale:<P>
|
|
</B><P>
|
|
If <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> is intended to resemble <A REL=DEFINITION HREF="../Body/s_let_l.htm#let"><B>LET</B></A> in syntax, it ought to<P>
|
|
allow declarations. When writing a <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> directly, the user<P>
|
|
could just as easily write a <A REL=DEFINITION HREF="../Body/s_the.htm#the"><B>THE</B></A> expression instead of a type<P>
|
|
declaration. However, when invoking a macro such as <A REL=DEFINITION HREF="../Body/m_w_slts.htm#with-slots"><B>WITH-SLOTS</B></A> that<P>
|
|
expands into <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A>, the user does not have this option since<P>
|
|
the expansion is not supplied explicitly by the user.<P>
|
|
<P>
|
|
<B>Current practice:<P>
|
|
</B><P>
|
|
<A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> was only tentatively added to Common Lisp 3 months ago.<P>
|
|
<P>
|
|
<B>Cost to Implementors:<P>
|
|
</B><P>
|
|
Less than one man-hour.<P>
|
|
<P>
|
|
<B>Cost to Users:<P>
|
|
</B><P>
|
|
None.<P>
|
|
<P>
|
|
<B>Cost of non-adoption:<P>
|
|
</B><P>
|
|
Minor wart in the language.<P>
|
|
<P>
|
|
<B>Benefits:<P>
|
|
</B><P>
|
|
More consistent language definition.<P>
|
|
<P>
|
|
<B>Esthetics:<P>
|
|
</B><P>
|
|
More consistent language definition.<P>
|
|
<P>
|
|
<B>Discussion:<P>
|
|
</B><P>
|
|
This issue is related to <A HREF="iss338.htm">SYMBOL-MACROLET-SEMANTICS</A>.<P>
|
|
<P>
|
|
"A macro-definition for <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A> would leave the issue of<P>
|
|
<A REL=DEFINITION HREF="../Body/s_declar.htm#declare"><B>DECLARE</B></A> open. But the special-form version of <A REL=DEFINITION HREF="../Body/s_symbol.htm#symbol-macrolet"><B>SYMBOL-MACROLET</B></A><P>
|
|
really should address it."<P>
|
|
<P>
|
|
</PRE>
|
|
<HR>
|
|
|
|
<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>
|
|
|
|
<A REL=COPYRIGHT HREF="../Front/Help.htm#Legal"><I>Copyright 1996-2005, LispWorks Ltd. All rights reserved.</I></A><P>
|
|
</BODY>
|
|
</HTML>
|