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<html><head><title>XLISP :isnew</title>
<link rel="stylesheet" type="text/css" href="reference.css">
</head>
<body>
<a href="../start.htm">Nyquist / XLISP 2.0</a> -
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<hr>
<h1>:isnew</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>message selector</nobr></td>
</tr>
<tr valign="top">
<td><nobr>Source:</nobr></td>
<td><nobr> - </nobr></td>
<td width="100%"><nobr>xlobj.c</nobr></td>
</tr>
</tbody></table></p>
<h2>Syntax</h2>
<dl>
<dt>(send <i>object</i> :isnew <i>args</i>)</dt>
<dd><i>object</i> - an existing object<br>
<i>args</i> - the arguments to be passed to the init code<br>
returns - the object</dd>
</dl>
<dl>
<dt>(send <i>class</i> :isnew <i>ivars</i> [<i>cvars</i> [<i>superclass</i>]])</dt>
<dd><i>class</i> - an existing XLISP class<br>
<i>ivars</i> - list of instance variables for the new class<br>
<i>cvars</i> - list of class variable symbols for the new class<br>
<i>superclass</i> - superclass for the new object, default is
<a href="object.htm">object</a><br>
returns - the new class object</dd>
</dl>
<h2>Description</h2>
<p>The ':isnew' message selector causes an instance to run its
initialization method. If an ':isnew' message is sent to a class, the class
definition and state will be reset as specified in the arguments of the
message.</p>
<h2>Examples</h2>
<pre class="example">
(setq a-class (send class :new '(state))) <font color="#008844">; create a new class A-CLASS with STATE</font>
(send a-class :answer :isnew '() <font color="#008844">; set up initialization</font>
'((setq state nil) self))
(send a-class :answer :set-it '(value) <font color="#008844">; create :SET-IT message</font>
'((setq state value)))
(setq an-obj (send a-class :new)) <font color="#008844">; create AN-OBJ out of A-CLASS</font>
(send an-obj :show) <font color="#008844">; returns object - STATE = NIL</font>
(send an-obj :set-it 5) <font color="#008844">; STATE is set to 5</font>
(send an-obj :show) <font color="#008844">; returns object - STATE = 5</font>
(SEND an-obj :ISNEW) <font color="#008844">; re-initialize AN-OBJ</font>
(send an-obj :show) <font color="#008844">; returns object - STATE = NIL</font>
</pre>
<p>See the
<a href="../manual/xlisp-man-010.htm#object-isnew">:isnew</a>
message selector in the <nobr>XLISP 2.0</nobr> manual.</p>
<p><nobr> <a href="#top">Back to Top</nobr></a></p>
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