擅长:python、mysql、java
<p>我相信你看到的是<a href="http://www.python.org/dev/peps/pep-3134/" rel="noreferrer">exception chaining</a>的结果,也就是<a href="http://docs.python.org/3.1/whatsnew/3.0.html#changes-to-exceptions" rel="noreferrer">change in Python 3</a>。</p>
<p>从政治公众人物的动机部分:</p>
<blockquote>
<p>During the handling of one exception (exception <code>A</code>), it is possible that another exception (exception <code>B</code>) may occur. In today's Python (version 2.4), if this happens, exception <code>B</code> is propagated outward and exception <code>A</code> is lost. In order to debug the problem, it is useful to know about both exceptions. The <code>__context__</code> attribute retains this information automatically.</p>
</blockquote>
<p>PEP接着详细描述了新的异常链(在Py3k中实现),这是一篇有趣的文章。我今天学到了新的东西。</p>