65 lines
4.9 KiB
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65 lines
4.9 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: Macro WITH-OPEN-STREAM</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_close.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="c_stream.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="f_listen.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<A NAME="with-open-stream"><I>Macro</I> <B>WITH-OPEN-STREAM</B></A> <P>
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<P>
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<P><B>Syntax:</B><P>
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<P>
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<B>with-open-stream</B> <I>(var stream) <I>declaration</I><B>*</B> <I>form</I><B>*</B></I><P> => <I><I>result</I><B>*</B></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>var</I>---a <A REL=DEFINITION HREF="26_glo_v.htm#variable"><I>variable</I></A> <A REL=DEFINITION HREF="26_glo_n.htm#name"><I>name</I></A>. <P>
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<I>stream</I>---a <A REL=DEFINITION HREF="26_glo_f.htm#form"><I>form</I></A>; evaluated to produce a <A REL=DEFINITION HREF="26_glo_s.htm#stream"><I>stream</I></A>. <P>
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<I>declaration</I>---a <A REL=DEFINITION HREF="s_declar.htm#declare"><B>declare</B></A> <A REL=DEFINITION HREF="26_glo_e.htm#expression"><I>expression</I></A>; not evaluated. <P>
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<I>forms</I>---an <A REL=DEFINITION HREF="26_glo_i.htm#implicit_progn"><I>implicit progn</I></A>. <P>
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<I>results</I>---the <A REL=DEFINITION HREF="26_glo_v.htm#value"><I>values</I></A> returned by the <I>forms</I>. <P>
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<P><B>Description:</B><P>
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<P>
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<A REL=DEFINITION HREF="#with-open-stream"><B>with-open-stream</B></A> performs a series of operations on <I>stream</I>, returns a value, and then closes the <I>stream</I>. <P>
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<I>Var</I> is bound to the value of <I>stream</I>, and then <I>forms</I> are executed as an <A REL=DEFINITION HREF="26_glo_i.htm#implicit_progn"><I>implicit progn</I></A>. <I>stream</I> is automatically closed on exit from <A REL=DEFINITION HREF="#with-open-stream"><B>with-open-stream</B></A>, no matter whether the exit is normal or abnormal. The <I>stream</I> has <A REL=DEFINITION HREF="26_glo_d.htm#dynamic_extent"><I>dynamic extent</I></A>; its <A REL=DEFINITION HREF="26_glo_e.htm#extent"><I>extent</I></A> ends when the <A REL=DEFINITION HREF="26_glo_f.htm#form"><I>form</I></A> is exited. <P>
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The consequences are undefined if an attempt is made to <A REL=DEFINITION HREF="26_glo_a.htm#assign"><I>assign</I></A> the the <A REL=DEFINITION HREF="26_glo_v.htm#variable"><I>variable</I></A> <I>var</I> with the <I>forms</I>. <P>
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<P><B>Examples:</B><P>
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<P>
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<PRE>
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(with-open-stream (s (make-string-input-stream "1 2 3 4"))
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(+ (read s) (read s) (read s))) => 6
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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 <I>stream</I> is closed (upon exit). <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_close.htm#close"><B>close</B></A> <P>
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<P><B>Notes:</B> None.
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<P>
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<P>
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<P><HR>The following <A REL=META HREF="../Front/X3J13Iss.htm">X3J13 cleanup issues</A>, <I>not part of the specification</I>, apply to this section:<P><UL><LI> <A REL=CHILD HREF="../Issues/iss362.htm">WITH-OPEN-FILE-SETQ:EXPLICITLY-VAGUE</A><LI> <A REL=CHILD HREF="../Issues/iss363.htm">WITH-OPEN-FILE-STREAM-EXTENT:DYNAMIC-EXTENT</A><LI> <A REL=CHILD HREF="../Issues/iss097.htm">DECLS-AND-DOC</A><P></UL><HR>
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