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<HTML><HEAD><TITLE>Answer to Exercise 16</TITLE></HEAD>
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<BODY BGCOLOR="#FFFFFF">
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<TABLE><TR><TD Valign="top"><IMG SRC="../icons/exercise.gif" ALT="??"><TD bgcolor="#FAA89B"><B>ANSWER TO EXERCISE 16</B><TR><TD><TD>
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Insert these lines into the <TT>before</TT> rule for <TT>PushDir</TT>:
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if (second==u_obj) <<PushDir self n_obj>>;
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if (second==d_obj) <<PushDir self s_obj>>;
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<HR>Back to <A HREF="../section14.html#ex16">the exercise in section 14</A><HR>
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<SMALL><I>Mechanically translated to HTML from third edition as revised 16 May 1997. Copyright © Graham Nelson 1993, 1994, 1995, 1996, 1997: all rights reserved.</I></SMALL></BODY></HTML>