93 lines
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93 lines
5.6 KiB
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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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<TITLE>CLHS: Special Operator LOCALLY</TITLE>
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<A NAME="locally"><I>Special Operator</I> <B>LOCALLY</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>locally</B> <I><I>declaration</I><B>*</B> <I>form</I><B>*</B></I> => <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>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> of the <I>forms</I>. <P>
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<P><B>Description:</B><P>
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<P>
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Sequentially evaluates a body of <I>forms</I> in a <A REL=DEFINITION HREF="26_glo_l.htm#lexical_environment"><I>lexical environment</I></A> where the given <I>declarations</I> have effect. <P>
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<P><B>Examples:</B><P>
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<P>
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<PRE>
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(defun sample-function (y) ;this y is regarded as special
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(declare (special y))
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(let ((y t)) ;this y is regarded as lexical
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(list y
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(locally (declare (special y))
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;; this next y is regarded as special
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y))))
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=> SAMPLE-FUNCTION
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(sample-function nil) => (T NIL)
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(setq x '(1 2 3) y '(4 . 5)) => (4 . 5)
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;;; The following declarations are not notably useful in specific.
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;;; They just offer a sample of valid declaration syntax using LOCALLY.
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(locally (declare (inline floor) (notinline car cdr))
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(declare (optimize space))
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(floor (car x) (cdr y))) => 0, 1
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</PRE>
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</TT> <P>
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<PRE>
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;;; This example shows a definition of a function that has a particular set
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;;; of OPTIMIZE settings made locally to that definition.
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(locally (declare (optimize (safety 3) (space 3) (speed 0)))
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(defun frob (w x y &optional (z (foo x y)))
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(mumble x y z w)))
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=> FROB
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;;; This is like the previous example, except that the optimize settings
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;;; remain in effect for subsequent definitions in the same compilation unit.
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(declaim (optimize (safety 3) (space 3) (speed 0)))
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(defun frob (w x y &optional (z (foo x y)))
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(mumble x y z w))
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=> FROB
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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="s_declar.htm#declare"><B>declare</B></A> <P>
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<P><B>Notes:</B><P>
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<P>
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The <A REL=DEFINITION HREF="d_specia.htm#special"><B>special</B></A> declaration may be used with <A REL=DEFINITION HREF="#locally"><B>locally</B></A> to affect references to, rather than <A REL=DEFINITION HREF="26_glo_b.htm#binding"><I>bindings</I></A> of, <A REL=DEFINITION HREF="26_glo_v.htm#variable"><I>variables</I></A>. <P>
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If a <A REL=DEFINITION HREF="#locally"><B>locally</B></A> <A REL=DEFINITION HREF="26_glo_f.htm#form"><I>form</I></A> is a <A REL=DEFINITION HREF="26_glo_t.htm#top_level_form"><I>top level form</I></A>, the body <I>forms</I> are also processed as <A REL=DEFINITION HREF="26_glo_t.htm#top_level_form"><I>top level forms</I></A>. See <A REL=CHILD HREF="03_bc.htm">Section 3.2.3 (File Compilation)</A>. <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/iss299.htm">RETURN-VALUES-UNSPECIFIED:SPECIFY</A><LI> <A REL=CHILD HREF="../Issues/iss219.htm">LOCALLY-TOP-LEVEL:SPECIAL-FORM</A><LI> <A REL=CHILD HREF="../Issues/iss097.htm">DECLS-AND-DOC</A><P></UL><HR>
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