<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <title>Programming Ruby: The Pragmatic Programmer's Guide</title> <link rel="StyleSheet" href="pr_style.css" type="text/css" media="screen"> </head> <body bgcolor="white"> <table bgcolor="#c09090" cellpadding="3" border="0" cellspacing="0" width="100%"> <tr> <td colspan="3"> <table bgcolor="#701a1a" cellpadding="20" width="100%"> <tr> <td width="6in"> <h1 class="header">Programming Ruby</h1> <h3 class="subheader">The Pragmatic Programmer's Guide</h3> </td> </tr> </table> </td> </tr> <tr> <td width="33%" align="left"> <a class="subheader" href="ref_c_exception.html">Previous <</a> </td> <td width="33%" align="center" valign="middle"> <a class="subheader" href="builtins.html">Contents ^</a> <br> </td> <td width="33%" align="right"> <a class="subheader" href="ref_c_file.html">Next ></a> <br> </td> </tr> </table> <!-- Copyright (c) 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). <P></P> Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. <P></P> Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder. --> <table> <tr> <td height="20"><img src="dot.gif" width="1" height="20"></td> </tr> </table> <table border="0" width="100%" bgcolor="660066" cellpadding="10"> <tr> <td valign="center"> <font color="white" size="7">class FalseClass</font> </td> <td> <table border="0"> <tr> <td> <font color="white"> Parent: </font> </td> <td> <font color="white">Object</font> </td> </tr> <tr> <td> <font color="white"> Version: </font> </td> <td> <font color="white"> 1.6 </font> </td> </tr> </table> </td> </tr> </table> <p></p> <H3>Index:</H3> <i> <a href="#FalseClass._et">&</a> </i> <i> <a href="#FalseClass._up">^</a> </i> <i> <a href="#FalseClass._ba">|</a> </i> <p></p> <hr> The global value <code>false</code> is the only instance of class <code>FalseClass</code> and represents a logically false value in boolean expressions. The class provides operators allowing <code>false</code> to participate correctly in logical expressions. <P></P> <table border="0" width="100%" cellpadding="10"> <tr> <td valign="center" colspan="2" bgcolor="990066"> <font color="white" size="6">instance methods </font> </td> </tr> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="FalseClass._et">&</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <code>false</code> & <i>anObject</i> -> <code>false</code> </td> </tr> <td></td> <td> <P></P> And---Returns <code>false</code>. <i>anObject</i> is always evaluated as it is the argument to a method call---there is no short-circuit evaluation in this case. <P></P> </td> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="FalseClass._up">^</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <code>false</code> ^ <i>anObject</i> -> <code>true</code> or <code>false</code> </td> </tr> <td></td> <td> <P></P> Exclusive Or---If <i>anObject</i> is <code>nil</code> or <code>false</code>, returns <code>false</code>; otherwise, returns <code>true</code>. <P></P> </td> <tr> <td valign="center" bgcolor="#ff9999"> <font size="4"> <b> <a name="FalseClass._ba">|</a> </b> </font> </td> <td bgcolor="#ffaaaa"> <code>false</code> | <i>anObject</i> -> <code>true</code> or <code>false</code> </td> </tr> <td></td> <td> <P></P> Or---Returns <code>false</code> if <i>anObject</i> is <code>nil</code> or <code>false</code>; <code>true</code> otherwise. <P></P> </td> </table> <P></P> <p></p> <hr> <table bgcolor="#a03030" cellpadding="10" border="0" cellspacing="0"> <tr> <td width="33%" align="left"> <a class="subheader" href="ref_c_exception.html">Previous <</a> </td> <td width="33%" align="center" valign="middle"> <a class="subheader" href="builtins.html">Contents ^</a> <br> </td> <td width="33%" align="right"> <a class="subheader" href="ref_c_file.html">Next ></a> <br> </td> </tr> </table> <p></p> <font size="-1">Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide"</font> <br> <font size="-3"> Copyright © 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at <a href="http://www.opencontent.org/openpub/">http://www.opencontent.org/openpub/</a>)). <p></p> Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. <p></p> Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder. <br> </font> </body> </html>