74 lines
7.7 KiB
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74 lines
7.7 KiB
HTML
<!-- Common Lisp HyperSpec (TM), version 7.0 generated by Kent M. Pitman on Mon, 11-Apr-2005 2:31am EDT -->
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<TITLE>CLHS: Function INTERN</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="m_do_sym.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="f_pkg_na.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<A NAME="intern"><I>Function</I> <B>INTERN</B></A> <P>
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<P><B>Syntax:</B><P>
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<P>
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<B>intern</B> <I>string <TT>&optional</TT> package</I> => <I>symbol, status</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>string</I>---a <A REL=DEFINITION HREF="26_glo_s.htm#string"><I>string</I></A>. <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>. <P>
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<I>symbol</I>---a <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A>. <P>
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<I>status</I>---one of <TT>:inherited</TT>, <TT>:external</TT>, <TT>:internal</TT>, or <A REL=DEFINITION HREF="a_nil.htm#nil"><B>nil</B></A>. <P>
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<P><B>Description:</B><P>
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<P>
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<A REL=DEFINITION HREF="#intern"><B>intern</B></A> enters a <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> named <I>string</I> into <I>package</I>. If a <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> whose name is the same as <I>string</I> is already <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> in <I>package</I>, it is returned. If no such <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> is <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> in <I>package</I>, a new <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> with the given name is created and entered into <I>package</I> as an <A REL=DEFINITION HREF="26_glo_i.htm#internal_symbol"><I>internal symbol</I></A>, or as an <A REL=DEFINITION HREF="26_glo_e.htm#external_symbol"><I>external symbol</I></A> if the <I>package</I> is the <TT>KEYWORD</TT> package; <I>package</I> becomes the <A REL=DEFINITION HREF="26_glo_h.htm#home_package"><I>home package</I></A> of the created <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A>. <P>
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The first value returned by <A REL=DEFINITION HREF="#intern"><B>intern</B></A>, <I>symbol</I>, is the <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> that was found or created. The meaning of the <A REL=DEFINITION HREF="26_glo_s.htm#secondary_value"><I>secondary value</I></A>, <I>status</I>, is as follows: <P><DL><DT><TT>:internal</TT> <P><DD>
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The <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> was found and is <A REL=DEFINITION HREF="26_glo_p.htm#present"><I>present</I></A> in <I>package</I> as an <A REL=DEFINITION HREF="26_glo_i.htm#internal_symbol"><I>internal symbol</I></A>. <P>
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<DT><TT>:external</TT> <P><DD>
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The <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> was found and is <A REL=DEFINITION HREF="26_glo_p.htm#present"><I>present</I></A> as an <A REL=DEFINITION HREF="26_glo_e.htm#external_symbol"><I>external symbol</I></A>. <P>
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<DT><TT>:inherited</TT> <P><DD>
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The <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> was found and is inherited via <A REL=DEFINITION HREF="f_use_pk.htm#use-package"><B>use-package</B></A> (which implies that the <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> is internal). <P>
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<DT><A REL=DEFINITION HREF="a_nil.htm#nil"><B>nil</B></A> <P><DD>
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No pre-existing <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> was found, so one was created. <P>
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It is <A REL=DEFINITION HREF="26_glo_i.htm#implementation-dependent"><I>implementation-dependent</I></A> whether the <A REL=DEFINITION HREF="26_glo_s.htm#string"><I>string</I></A> that becomes the new <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A>'s <A REL=DEFINITION HREF="26_glo_n.htm#name"><I>name</I></A> is the given <I>string</I> or a copy of it. Once a <A REL=DEFINITION HREF="26_glo_s.htm#string"><I>string</I></A> has been given as the <I>string</I> <A REL=DEFINITION HREF="26_glo_a.htm#argument"><I>argument</I></A> to <A REL=DEFINITION HREF="26_glo_i.htm#intern"><I>intern</I></A> in this situation where a new <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> is created, the consequences are undefined if a subsequent attempt is made to alter that <A REL=DEFINITION HREF="26_glo_s.htm#string"><I>string</I></A>. <P>
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<P></DL><P>
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<P><B>Examples:</B><P>
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<P>
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<PRE>
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(in-package "COMMON-LISP-USER") => #<PACKAGE "COMMON-LISP-USER">
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(intern "Never-Before") => |Never-Before|, NIL
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(intern "Never-Before") => |Never-Before|, :INTERNAL
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(intern "NEVER-BEFORE" "KEYWORD") => :NEVER-BEFORE, NIL
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(intern "NEVER-BEFORE" "KEYWORD") => :NEVER-BEFORE, :EXTERNAL
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</PRE>
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</TT> <P>
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<P><B>Side Effects:</B> None.
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<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>
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<P><B>See Also:</B><P>
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<P>
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<A REL=DEFINITION HREF="f_find_s.htm#find-symbol"><B>find-symbol</B></A>, <A REL=DEFINITION HREF="f_rd_rd.htm#read"><B>read</B></A>, <A REL=DEFINITION HREF="t_symbol.htm#symbol"><B>symbol</B></A>, <A REL=DEFINITION HREF="f_uninte.htm#unintern"><B>unintern</B></A>, <A REL=CHILD HREF="02_cd.htm">Section 2.3.4 (Symbols as Tokens)</A> <P>
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<P><B>Notes:</B><P>
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<P>
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<A REL=DEFINITION HREF="#intern"><B>intern</B></A> does not need to do any name conflict checking because it never creates a new <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> if there is already an <A REL=DEFINITION HREF="26_glo_a.htm#accessible"><I>accessible</I></A> <A REL=DEFINITION HREF="26_glo_s.htm#symbol"><I>symbol</I></A> with the name given. <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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