docsrc/xlisp/xlisp-doc/reference/t.htm


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<html><head><title>XLISP t</title>

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</head>

<body>

<a href="../start.htm">Nyquist / XLISP 2.0</a>&nbsp; -&nbsp;
<a href="../manual/contents.htm">Contents</a> |
<a href="../tutorials/tutorials.htm">Tutorials</a> |
<a href="../examples/examples.htm">Examples</a> |
<a href="reference-index.htm">Reference</a>

<hr>

<h1>t</h1>

<hr>

<p><table cellpadding="0" cellspacing="0" style="margin-left:10px"><tbody>
<tr valign="top">
  <td><nobr>Type:</nobr></td>
  <td><nobr>&nbsp;&nbsp;-&nbsp;&nbsp;</nobr></td>
  <td width="100%"><nobr>system constant</nobr></td>
</tr>
<tr valign="top">
  <td><nobr>Source:</nobr></td>
  <td><nobr>&nbsp;&nbsp;-&nbsp;&nbsp;</nobr></td>
  <td width="100%"><nobr>xlinit.c</nobr></td>
</tr>
</tbody></table></p>

<h2>Syntax</h2>

<dl>
<dt>&nbsp;t</dt>
</dl>

<h2>Description</h2>

<p>The T system constant is built into XLISP. T represents 'true',
as oppossed to <nobr><a href="nil.htm">NIL</a> ,</nobr>
representing 'false'.</p>

<h2>Examples</h2>

<pre class="example">
(setq myvar T)                     <font color="#008844">; set MYVAR to True</font>
(setq myvar 'T)                    <font color="#008844">; T and 'T both evaluate to T</font>
(if t (print "this will print")    <font color="#008844">; if, then, else</font>
      (print "this won't print"))
</pre>

<p><b>Note:</b> Be careful with the T value. It is possible to do a
<a href="setq.htm">setq</a> on T and set it to other values like
<a href="nil.htm">NIL</a>. Some operations will still return
proper T or <a href="nil.htm">NIL</a> values, but the system
will be in a bad state.</p>

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<a href="../examples/examples.htm">Examples</a> |
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