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<html><head><title>XLISP :constituent</title>
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</head>
<body>
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<hr>
<h1>:constituent</h1>
<hr>
<p><table cellpadding="0" cellspacing="0" style="margin-left:10px"><tbody>
<tr valign="top">
<td><nobr>Type:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>keyword</nobr></td>
</tr>
<tr valign="top">
<td><nobr>Source:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>xlread.c</nobr></td>
</tr>
</tbody></table></p>
<h2>Syntax</h2>
<dl>
<dt> :constituent</dt>
</dl>
<h2>Description</h2>
<p>':constituent' is an entry that is used in the
<a href="global-readtable.htm">*readtable*</a> system variable that
contains XLISP's data structures relating to the processing of characters
from the user [or files] and read-macro expansions. The existance of the
':constituent' keyword means that the specified character is to be used, as
is, with no further processing. The system defines that the following
characters are ':constituent' characters:</p>
<pre class="example">
0123456789
!$%&*+-./:<=>?@[]^_{}~
ABCDEFGHIJKLMNOPQRSTUVWXYZ
abcdefghijklmnopqrstuvwxyz
</pre>
<h2>Examples</h2>
<pre class="example">
(defun look-at (table) <font color="#008844">; define a function to</font>
(dotimes (ch 127) <font color="#008844">; look in a table</font>
(prog ((entry (aref table ch))) <font color="#008844">; and print out any</font>
(case entry <font color="#008844">; entries with a function</font>
(:CONSTITUENT
(princ (int-char ch)))
(T NIL))))
(terpri))
(look-at *readtable*) <font color="#008844">; prints !$%&*+-./0123456789</font>
<font color="#008844">; :<=>?@ABCDEFGHIJKLM</font>
<font color="#008844">; NOPQRSTUVWXYZ[]^_ab</font>
<font color="#008844">; cdefghijklmnopqrstu</font>
<font color="#008844">; vwxyz{}~</font>
</pre>
<p><b>Caution:</b> If you experiment with
<nobr><a href="global-readtable.htm">*readtable*</a> ,</nobr> it is useful to
save the old value in a variable, so that you can restore the system
state.</p>
<p>See the
<a href="../manual/xlisp-man-008.htm#constituent">:constituent</a>
keyword in the <nobr>XLISP 2.0</nobr> manual.</p>
<p><nobr> <a href="#top">Back to Top</nobr></a></p>
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