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<h1 class="header">Programming Ruby</h1>
<h3 class="subheader">The Pragmatic Programmer's Guide</h3>
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Copyright (c) 2001 by Addison Wesley Longman, Inc. This material may
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<font color="white" size="7">class Exception</font>
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Parent:
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<font color="white">Object</font>
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Version:
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1.6
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<p></p>
<H3>Index:</H3>
<a href="#Exception.exception">exception</a>
<i>
<a href="#Exception.backtrace">backtrace</a>
</i> <i>
<a href="#Exception.exception">exception</a>
</i> <i>
<a href="#Exception.message">message</a>
</i> <i>
<a href="#Exception.set_backtrace">set_backtrace</a>
</i> <p></p>
<hr>
<P></P>
Descendents of class <code>Exception</code> are used to communicate
between <code>raise</code>
methods and <code>rescue</code> statements in <code>begin/end</code>
blocks. <code>Exception</code> objects carry information about the
exception---its type (the exception's class name), an optional
descriptive string, and optional traceback information.
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<font color="white" size="6">class methods
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<b>
<a name="Exception.exception">exception</a>
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Exception.exception( <i>[</i>
<i>aString</i>
<i>]</i> )
-> <i>anException</i>
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<P></P>
Creates and returns a new exception object, optionally setting the message to
<i>aString</i>.
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<font color="white" size="6">instance methods
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<b>
<a name="Exception.backtrace">backtrace</a>
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<i>exc</i>.backtrace
-> <i>anArray</i>
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Returns any backtrace associated with the exception. The
backtrace is an array of strings, each containing
either ``filename:lineNo: in `method''' or ``filename:lineNo.''
<P></P>
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<pre>
def a
raise "boom"
end
<P></P>
def b
a()
end
<P></P>
begin
b()
rescue => detail
print detail.backtrace.join("\n")
end
</pre>
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<em>produces:</em>
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<pre>
prog.rb:2:in `a'
prog.rb:6:in `b'
prog.rb:10
</pre>
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<b>
<a name="Exception.exception">exception</a>
</b>
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<i>exc</i>.exception( <i>[</i>
<i>aString</i>
<i>]</i> )
-> <i>anException</i> or <i>exc</i>
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With no argument, returns the receiver. Otherwise, creates a new
exception object of the same class as the receiver, but with a
different message.
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<b>
<a name="Exception.message">message</a>
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<i>exc</i>.message -> <i>aString</i>
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Returns the message associated with this exception.
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<b>
<a name="Exception.set_backtrace">set_backtrace</a>
</b>
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<i>exc</i>.set_backtrace( <i>anArray</i> )
-> <i>anArray</i>
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<P></P>
Sets the backtrace information associated with <i>exc</i>. The
argument must be an array of <code>String</code> objects in the format
described in <a href="ref_c_exception.html#Exception.backtrace">
<code>Exception#backtrace</code>
</a>.
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<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.
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