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6.4 KiB
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65 lines
6.4 KiB
HTML
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<!-- Common Lisp HyperSpec (TM), version 7.0 generated by Kent M. Pitman on Mon, 11-Apr-2005 2:31am EDT -->
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<HTML>
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<HEAD>
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<TITLE>CLHS: Function USE-PACKAGE</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="f_unuse_.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="c_packag.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="m_defpkg.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<HR>
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<A NAME="use-package"><I>Function</I> <B>USE-PACKAGE</B></A> <P>
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<P><B>Syntax:</B><P>
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<P>
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<B>use-package</B> <I>packages-to-use <TT>&optional</TT> package</I> => <I><A REL=DEFINITION HREF="a_t.htm#t"><B>t</B></A></I><P>
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<P>
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<P><B>Arguments and Values:</B><P>
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<P>
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<I>packages-to-use</I>---a <A REL=DEFINITION HREF="26_glo_d.htm#designator"><I>designator</I></A> for a <A REL=DEFINITION HREF="26_glo_l.htm#list"><I>list</I></A> of <A REL=DEFINITION HREF="26_glo_p.htm#package_designator"><I>package designators</I></A>. The <TT>KEYWORD</TT> package may not be supplied. <P>
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<I>package</I>---a <A REL=DEFINITION HREF="26_glo_p.htm#package_designator"><I>package designator</I></A>. The default is the <A REL=DEFINITION HREF="26_glo_c.htm#current_package"><I>current package</I></A>. The <I>package</I> cannot be the <TT>KEYWORD</TT> package. <P>
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<P><B>Description:</B><P>
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<P>
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<A REL=DEFINITION HREF="#use-package"><B>use-package</B></A> causes <I>package</I> to inherit all the <A REL=DEFINITION HREF="26_glo_e.htm#external_symbol"><I>external symbols</I></A> of <I>packages-to-use</I>. The inherited <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbols</I></A> become <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> as <A REL=DEFINITION HREF="26_glo_i.htm#internal_symbol"><I>internal symbols</I></A> of <I>package</I>. <P>
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<I>Packages-to-use</I> are added to the <A REL=DEFINITION HREF="26_glo_u.htm#use_list"><I>use list</I></A> of <I>package</I> if they are not there already. All <A REL=DEFINITION HREF="26_glo_e.htm#external_symbol"><I>external symbols</I></A> in <I>packages-to-use</I> become <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> in <I>package</I> as <A REL=DEFINITION HREF="26_glo_i.htm#internal_symbol"><I>internal symbols</I></A>. <A REL=DEFINITION HREF="#use-package"><B>use-package</B></A> does not cause any new <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbols</I></A> to be <A REL=DEFINITION HREF="26_glo_p.htm#present"><I>present</I></A> in <I>package</I> but only makes them <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> by inheritance. <P>
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<A REL=DEFINITION HREF="#use-package"><B>use-package</B></A> checks for name conflicts between the newly imported symbols and those already <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> in <I>package</I>. A name conflict in <A REL=DEFINITION HREF="#use-package"><B>use-package</B></A> between two external symbols inherited by <I>package</I> from <I>packages-to-use</I> may be resolved in favor of either <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> by <I>importing</I> one of them into <I>package</I> and making it a shadowing symbol. <P>
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<P><B>Examples:</B><P>
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<P>
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<PRE>
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(export (intern "LAND-FILL" (make-package 'trash)) 'trash) => T
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(find-symbol "LAND-FILL" (make-package 'temp)) => NIL, NIL
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(package-use-list 'temp) => (#<PACKAGE "TEMP">)
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(use-package 'trash 'temp) => T
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(package-use-list 'temp) => (#<PACKAGE "TEMP"> #<PACKAGE "TRASH">)
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(find-symbol "LAND-FILL" 'temp) => TRASH:LAND-FILL, :INHERITED
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</PRE>
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</TT> <P>
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<P><B>Side Effects:</B><P>
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<P>
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The <A REL=DEFINITION HREF="26_glo_u.htm#use_list"><I>use list</I></A> of <I>package</I> may be modified. <P>
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<P><B>Affected By:</B> None.
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<P>
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<P><B>Exceptional Situations:</B> None.
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<P><B>See Also:</B><P>
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<P>
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<A REL=DEFINITION HREF="f_unuse_.htm#unuse-package"><B>unuse-package</B></A>, <A REL=DEFINITION HREF="f_pkg_us.htm#package-use-list"><B>package-use-list</B></A>, <A REL=CHILD HREF="11_a.htm">Section 11.1 (Package Concepts)</A> <P>
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<P><B>Notes:</B><P>
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<P>
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It is permissible for a <A REL=DEFINITION HREF="26_glo_p.htm#package"><I>package</I></A> P1 to <A REL=DEFINITION HREF="26_glo_u.htm#use"><I>use</I></A> a <A REL=DEFINITION HREF="26_glo_p.htm#package"><I>package</I></A> P2 even if P2 already uses P1. The using of <A REL=DEFINITION HREF="26_glo_p.htm#package"><I>packages</I></A> is not transitive, so no problem results from the apparent circularity. <P>
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<P><HR>The following <A REL=META HREF="../Front/X3J13Iss.htm">X3J13 cleanup issue</A>, <I>not part of the specification</I>, applies to this section:<P><UL><LI> <A REL=CHILD HREF="../Issues/iss254.htm">PACKAGE-FUNCTION-CONSISTENCY:MORE-PERMISSIVE</A><P></UL><HR>
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<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>
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<A REL=COPYRIGHT HREF="../Front/Help.htm#Legal"><I>Copyright 1996-2005, LispWorks Ltd. All rights reserved.</I></A><P>
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