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41 lines
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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: Section 4.3.4.1</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="04_cd.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Previous]" SRC="../Graphics/Prev.gif" ALIGN=Bottom></A><A REL=UP HREF="04_cd.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Up]" SRC="../Graphics/Up.gif" ALIGN=Bottom></A><A REL=NEXT HREF="04_cdb.htm"><IMG WIDTH=40 HEIGHT=40 ALT="[Next]" SRC="../Graphics/Next.gif" ALIGN=Bottom></A></H1>
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<H2>
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4.3.4.1 Examples of Inheritance</H2> <P>
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<PRE>
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(defclass C1 ()
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((S1 :initform 5.4 :type number)
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(S2 :allocation :class)))
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(defclass C2 (C1)
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((S1 :initform 5 :type integer)
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(S2 :allocation :instance)
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(S3 :accessor C2-S3)))
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</PRE>
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</TT> <P>
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<A REL=DEFINITION HREF="26_glo_i.htm#instance"><I>Instances</I></A> of the class <TT>C1</TT> have a <A REL=DEFINITION HREF="26_glo_l.htm#local_slot"><I>local slot</I></A> named <TT>S1</TT>, whose default initial value is 5.4 and whose <A REL=DEFINITION HREF="26_glo_v.htm#value"><I>value</I></A> should always be a <A REL=DEFINITION HREF="26_glo_n.htm#number"><I>number</I></A>. The class <TT>C1</TT> also has a <A REL=DEFINITION HREF="26_glo_s.htm#shared_slot"><I>shared slot</I></A> named <TT>S2</TT>. <P>
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There is a <A REL=DEFINITION HREF="26_glo_l.htm#local_slot"><I>local slot</I></A> named <TT>S1</TT> in <A REL=DEFINITION HREF="26_glo_i.htm#instance"><I>instances</I></A> of <TT>C2</TT>. The default initial value of <TT>S1</TT> is 5. The value of <TT>S1</TT> should always be of type <TT>(and integer number)</TT>. There are also <A REL=DEFINITION HREF="26_glo_l.htm#local_slot"><I>local slots</I></A> named <TT>S2</TT> and <TT>S3</TT> in <A REL=DEFINITION HREF="26_glo_i.htm#instance"><I>instances</I></A> of <TT>C2</TT>. The class <TT>C2</TT> has a <A REL=DEFINITION HREF="26_glo_m.htm#method"><I>method</I></A> for <TT>C2-S3</TT> for reading the value of slot <TT>S3</TT>; there is also a <A REL=DEFINITION HREF="26_glo_m.htm#method"><I>method</I></A> for <TT>(setf C2-S3)</TT> that writes the value of <TT>S3</TT>. <P>
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