uTools-Manuals/docs/python/code.html

<div class="body" role="main"><div class="section" id="module-code"><h1><span class="yiyi-st" id="yiyi-10">30.1. <a class="reference internal" href="#module-code" title="code: Facilities to implement read-eval-print loops."><code class="xref py py-mod docutils literal"><span class="pre">code</span></code></a>  - 解释器基类</span></h1><p><span class="yiyi-st" id="yiyi-11"><strong>源代码：</strong> <a class="reference external" href="https://hg.python.org/cpython/file/3.5/Lib/code.py">Lib / code.py</a></span></p><p><span class="yiyi-st" id="yiyi-12"><code class="docutils literal"><span class="pre">code</span></code>模块提供了在Python中实现read-eval-print循环的功能。</span><span class="yiyi-st" id="yiyi-13">包括两个类和便利功能，其可以用于构建提供交互式解释器提示的应用。</span></p><dl class="class"><dt id="code.InteractiveInterpreter"><span class="yiyi-st" id="yiyi-14"> <em class="property">class </em><code class="descclassname">code.</code><code class="descname">InteractiveInterpreter</code><span class="sig-paren">(</span><em>locals=None</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-15">None</span><span class="yiyi-st" id="yiyi-16">可选的<em>locals</em>参数指定将在其中执行代码的字典；默认为新创建的字典，键<code class="docutils literal"><span class="pre">'__name__'</span></code>设置为<code class="docutils literal"><span class="pre">'__console__'</span></code>，键<code class="docutils literal"><span class="pre">'__doc__'</span></code>设置为<code class="docutils literal"><span class="pre">None</span></code></span></p></dd></dl><dl class="class"><dt id="code.InteractiveConsole"><span class="yiyi-st" id="yiyi-17"> <em class="property">class </em><code class="descclassname">code.</code><code class="descname">InteractiveConsole</code><span class="sig-paren">(</span><em>locals=None</em>, <em>filename="&lt;console&gt;"</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-18">None</span><span class="yiyi-st" id="yiyi-19">此类构建在<a class="reference internal" href="#code.InteractiveInterpreter" title="code.InteractiveInterpreter"><code class="xref py py-class docutils literal"><span class="pre">InteractiveInterpreter</span></code></a>上，并使用熟悉的<code class="docutils literal"><span class="pre">sys.ps1</span></code>和<code class="docutils literal"><span class="pre">sys.ps2</span></code>添加提示，并输入缓冲。</span></p></dd></dl><dl class="function"><dt id="code.interact"><span class="yiyi-st" id="yiyi-20"> <code class="descclassname">code.</code><code class="descname">interact</code><span class="sig-paren">(</span><em>banner=None</em>, <em>readfunc=None</em>, <em>local=None</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-21">便利功能运行读取 - 打印回路。</span><span class="yiyi-st" id="yiyi-22">这将创建<a class="reference internal" href="#code.InteractiveConsole" title="code.InteractiveConsole"><code class="xref py py-class docutils literal"><span class="pre">InteractiveConsole</span></code></a>的新实例，并将<em>readfunc</em>设置为<a class="reference internal" href="#code.InteractiveConsole.raw_input" title="code.InteractiveConsole.raw_input"><code class="xref py py-meth docutils literal"><span class="pre">InteractiveConsole.raw_input()</span></code></a>方法（如果提供）。</span><span class="yiyi-st" id="yiyi-23">如果提供<em>local</em>，则会传递到<a class="reference internal" href="#code.InteractiveConsole" title="code.InteractiveConsole"><code class="xref py py-class docutils literal"><span class="pre">InteractiveConsole</span></code></a>构造函数，以用作解释器循环的默认命名空间。</span><span class="yiyi-st" id="yiyi-24">然后，实例的<a class="reference internal" href="#code.interact" title="code.interact"><code class="xref py py-meth docutils literal"><span class="pre">interact()</span></code></a>方法将作为横幅广告使用的<em>banner</em>运行（如果提供）。</span><span class="yiyi-st" id="yiyi-25">控制台对象在使用后将被丢弃。</span></p></dd></dl><dl class="function"><dt id="code.compile_command"><span class="yiyi-st" id="yiyi-26"> <code class="descclassname">code.</code><code class="descname">compile_command</code><span class="sig-paren">(</span><em>source</em>, <em>filename="&lt;input&gt;"</em>, <em>symbol="single"</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-27">这个函数对于想要模拟Python的解释器主循环（a.k.a.</span><span class="yiyi-st" id="yiyi-28">read-eval-print循环）。</span><span class="yiyi-st" id="yiyi-29">棘手的部分是确定用户何时输入了可以通过输入更多文本（而不是完整命令或语法错误）完成的不完整命令。</span><span class="yiyi-st" id="yiyi-30">此函数<em>几乎</em>总是做出与真实解释器主循环相同的决定。</span></p><p><span class="yiyi-st" id="yiyi-31"><em>源</em>是源字符串； <em>filename</em>是从中读取源的可选文件名，默认为<code class="docutils literal"><span class="pre">'&lt;input&gt;'</span></code>；和<em>符号</em>是可选的语法起始符号，应为<code class="docutils literal"><span class="pre">'single'</span></code>（默认值）或<code class="docutils literal"><span class="pre">'eval'</span></code>。</span></p><p><span class="yiyi-st" id="yiyi-32">如果命令完成，则返回一个代码对象（与<code class="docutils literal"><span class="pre">compile（source，</span> <span class="pre">filename，</span> <span class="pre">符号）</span></code>和有效； <code class="docutils literal"><span class="pre">None</span></code>如果命令不完整；如果命令包含无效的字面值，则如果命令完成且包含语法错误，则引发<a class="reference internal" href="exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal"><span class="pre">SyntaxError</span></code></a>，或引发<a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></code></a>或<a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal"><span class="pre">ValueError</span></code></a></span></p></dd></dl><div class="section" id="interactive-interpreter-objects"><h2><span class="yiyi-st" id="yiyi-33">30.1.1. </span><span class="yiyi-st" id="yiyi-34">交互式解释器对象</span></h2><dl class="method"><dt id="code.InteractiveInterpreter.runsource"><span class="yiyi-st" id="yiyi-35"> <code class="descclassname">InteractiveInterpreter.</code><code class="descname">runsource</code><span class="sig-paren">(</span><em>source</em>, <em>filename="&lt;input&gt;"</em>, <em>symbol="single"</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-36">在解释器中编译并运行一些源代码。</span><span class="yiyi-st" id="yiyi-37">参数与<a class="reference internal" href="#code.compile_command" title="code.compile_command"><code class="xref py py-func docutils literal"><span class="pre">compile_command()</span></code></a>相同； <em>filename</em>的默认值为<code class="docutils literal"><span class="pre">'&lt;input&gt;'</span></code>，<em>符号</em>的默认值为<code class="docutils literal"><span class="pre">'single'</span></code>。</span><span class="yiyi-st" id="yiyi-38">有几件事情可能发生：</span></p><ul class="simple"><li><span class="yiyi-st" id="yiyi-39">输入不正确； <a class="reference internal" href="#code.compile_command" title="code.compile_command"><code class="xref py py-func docutils literal"><span class="pre">compile_command()</span></code></a>引发了一个异常（<a class="reference internal" href="exceptions.html#SyntaxError" title="SyntaxError"><code class="xref py py-exc docutils literal"><span class="pre">SyntaxError</span></code></a>或<a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal"><span class="pre">OverflowError</span></code></a>）。</span><span class="yiyi-st" id="yiyi-40">将通过调用<a class="reference internal" href="#code.InteractiveInterpreter.showsyntaxerror" title="code.InteractiveInterpreter.showsyntaxerror"><code class="xref py py-meth docutils literal"><span class="pre">showsyntaxerror()</span></code></a>方法打印语法追溯。</span><span class="yiyi-st" id="yiyi-41"><a class="reference internal" href="#code.InteractiveInterpreter.runsource" title="code.InteractiveInterpreter.runsource"><code class="xref py py-meth docutils literal"><span class="pre">runsource()</span></code></a>返回<code class="docutils literal"><span class="pre">False</span></code>。</span></li><li><span class="yiyi-st" id="yiyi-42">输入不完整，需要更多的输入； <a class="reference internal" href="#code.compile_command" title="code.compile_command"><code class="xref py py-func docutils literal"><span class="pre">compile_command()</span></code></a>返回<code class="docutils literal"><span class="pre">None</span></code>。</span><span class="yiyi-st" id="yiyi-43"><a class="reference internal" href="#code.InteractiveInterpreter.runsource" title="code.InteractiveInterpreter.runsource"><code class="xref py py-meth docutils literal"><span class="pre">runsource()</span></code></a>返回<code class="docutils literal"><span class="pre">True</span></code>。</span></li><li><span class="yiyi-st" id="yiyi-44">输入完成； <a class="reference internal" href="#code.compile_command" title="code.compile_command"><code class="xref py py-func docutils literal"><span class="pre">compile_command()</span></code></a>返回了一个代码对象。</span><span class="yiyi-st" id="yiyi-45">通过调用<a class="reference internal" href="#code.InteractiveInterpreter.runcode" title="code.InteractiveInterpreter.runcode"><code class="xref py py-meth docutils literal"><span class="pre">runcode()</span></code></a>（它还处理运行时异常，除了<a class="reference internal" href="exceptions.html#SystemExit" title="SystemExit"><code class="xref py py-exc docutils literal"><span class="pre">SystemExit</span></code></a>）来执行代码。</span><span class="yiyi-st" id="yiyi-46"><a class="reference internal" href="#code.InteractiveInterpreter.runsource" title="code.InteractiveInterpreter.runsource"><code class="xref py py-meth docutils literal"><span class="pre">runsource()</span></code></a>返回<code class="docutils literal"><span class="pre">False</span></code>。</span></li></ul><p><span class="yiyi-st" id="yiyi-47">返回值可用于决定是使用<code class="docutils literal"><span class="pre">sys.ps1</span></code>还是<code class="docutils literal"><span class="pre">sys.ps2</span></code>提示下一行。</span></p></dd></dl><dl class="method"><dt id="code.InteractiveInterpreter.runcode"><span class="yiyi-st" id="yiyi-48"> <code class="descclassname">InteractiveInterpreter.</code><code class="descname">runcode</code><span class="sig-paren">(</span><em>code</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-49">执行代码对象。</span><span class="yiyi-st" id="yiyi-50">发生异常时，调用<a class="reference internal" href="#code.InteractiveInterpreter.showtraceback" title="code.InteractiveInterpreter.showtraceback"><code class="xref py py-meth docutils literal"><span class="pre">showtraceback()</span></code></a>以显示跟踪。</span><span class="yiyi-st" id="yiyi-51">除了<a class="reference internal" href="exceptions.html#SystemExit" title="SystemExit"><code class="xref py py-exc docutils literal"><span class="pre">SystemExit</span></code></a>，允许传播的所有异常都被捕获。</span></p><p><span class="yiyi-st" id="yiyi-52">关于<a class="reference internal" href="exceptions.html#KeyboardInterrupt" title="KeyboardInterrupt"><code class="xref py py-exc docutils literal"><span class="pre">KeyboardInterrupt</span></code></a>的注释：此异常可能会在此代码的其他位置发生，并且可能不会总是被捕获。</span><span class="yiyi-st" id="yiyi-53">调用者应该准备处理它。</span></p></dd></dl><dl class="method"><dt id="code.InteractiveInterpreter.showsyntaxerror"><span class="yiyi-st" id="yiyi-54"> <code class="descclassname">InteractiveInterpreter.</code><code class="descname">showsyntaxerror</code><span class="sig-paren">(</span><em>filename=None</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-55">显示刚刚发生的语法错误。</span><span class="yiyi-st" id="yiyi-56">这不显示堆栈跟踪，因为没有语法错误。</span><span class="yiyi-st" id="yiyi-57">如果给出了<em>filename</em>，它被填充到异常而不是由Python的解析器提供的默认文件名，因为它从字符串读取时总是使用<code class="docutils literal"><span class="pre">'&lt;string&gt;'</span></code> 。</span><span class="yiyi-st" id="yiyi-58">输出由<a class="reference internal" href="#code.InteractiveInterpreter.write" title="code.InteractiveInterpreter.write"><code class="xref py py-meth docutils literal"><span class="pre">write()</span></code></a>方法写入。</span></p></dd></dl><dl class="method"><dt id="code.InteractiveInterpreter.showtraceback"><span class="yiyi-st" id="yiyi-59"> <code class="descclassname">InteractiveInterpreter.</code><code class="descname">showtraceback</code><span class="sig-paren">(</span><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-60">显示刚刚发生的异常。</span><span class="yiyi-st" id="yiyi-61">我们删除第一个堆栈项，因为它在解释器对象实现中。</span><span class="yiyi-st" id="yiyi-62">输出由<a class="reference internal" href="#code.InteractiveInterpreter.write" title="code.InteractiveInterpreter.write"><code class="xref py py-meth docutils literal"><span class="pre">write()</span></code></a>方法写入。</span></p><div class="versionchanged"><p><span class="yiyi-st" id="yiyi-63"><span class="versionmodified">在版本3.5中更改：</span>显示完全链式跟踪，而不是仅显示主要跟踪。</span></p></div></dd></dl><dl class="method"><dt id="code.InteractiveInterpreter.write"><span class="yiyi-st" id="yiyi-64"> <code class="descclassname">InteractiveInterpreter.</code><code class="descname">write</code><span class="sig-paren">(</span><em>data</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-65">将一个字符串写入标准错误流（<code class="docutils literal"><span class="pre">sys.stderr</span></code>）。</span><span class="yiyi-st" id="yiyi-66">派生类应该覆盖此，以根据需要提供适当的输出处理。</span></p></dd></dl></div><div class="section" id="interactive-console-objects"><h2><span class="yiyi-st" id="yiyi-67">30.1.2. </span><span class="yiyi-st" id="yiyi-68">交互式控制台对象</span></h2><p><span class="yiyi-st" id="yiyi-69"><a class="reference internal" href="#code.InteractiveConsole" title="code.InteractiveConsole"><code class="xref py py-class docutils literal"><span class="pre">InteractiveConsole</span></code></a>类是<a class="reference internal" href="#code.InteractiveInterpreter" title="code.InteractiveInterpreter"><code class="xref py py-class docutils literal"><span class="pre">InteractiveInterpreter</span></code></a>的子类，因此提供了解释器对象的所有方法以及以下添加项。</span></p><dl class="method"><dt id="code.InteractiveConsole.interact"><span class="yiyi-st" id="yiyi-70"> <code class="descclassname">InteractiveConsole.</code><code class="descname">interact</code><span class="sig-paren">(</span><em>banner=None</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-71">密切地模拟交互式Python控制台。</span><span class="yiyi-st" id="yiyi-72">可选的<em>横幅</em>参数指定在首次交互之前打印的横幅；默认情况下，它打印一个类似于标准Python解释器打印的横幅，后面是括号中的控制台对象的类名（以免混淆到真正的解释器 - 因为它非常接近！</span><span class="yiyi-st" id="yiyi-73">）。</span></p><div class="versionchanged"><p><span class="yiyi-st" id="yiyi-74"><span class="versionmodified">在版本3.4中更改：</span>要禁止打印任何横幅，请传递一个空字符串。</span></p></div></dd></dl><dl class="method"><dt id="code.InteractiveConsole.push"><span class="yiyi-st" id="yiyi-75"> <code class="descclassname">InteractiveConsole.</code><code class="descname">push</code><span class="sig-paren">(</span><em>line</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-76">将一行源文本推送到解释器。</span><span class="yiyi-st" id="yiyi-77">该行不应该有一个尾随换行符；它可能有内部换行符。</span><span class="yiyi-st" id="yiyi-78">该行被附加到缓冲区，并且解释器的<code class="xref py py-meth docutils literal"><span class="pre">runsource()</span></code>方法以缓冲区的连接内容作为源来调用。</span><span class="yiyi-st" id="yiyi-79">如果这表示命令已执行或无效，则缓冲区复位；否则，命令不完整，并且缓冲区在添加行之后保留。</span><span class="yiyi-st" id="yiyi-80">如果需要更多输入，返回值为<code class="docutils literal"><span class="pre">True</span></code>，<code class="docutils literal"><span class="pre">False</span></code>如果以某种方式处理该行（这与<code class="xref py py-meth docutils literal"><span class="pre">runsource()</span></code></span></p></dd></dl><dl class="method"><dt id="code.InteractiveConsole.resetbuffer"><span class="yiyi-st" id="yiyi-81"> <code class="descclassname">InteractiveConsole.</code><code class="descname">resetbuffer</code><span class="sig-paren">(</span><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-82">从输入缓冲区中删除任何未处理的源文本。</span></p></dd></dl><dl class="method"><dt id="code.InteractiveConsole.raw_input"><span class="yiyi-st" id="yiyi-83"> <code class="descclassname">InteractiveConsole.</code><code class="descname">raw_input</code><span class="sig-paren">(</span><em>prompt=""</em><span class="sig-paren">)</span></span></dt><dd><p><span class="yiyi-st" id="yiyi-84">写一个提示并读一行。</span><span class="yiyi-st" id="yiyi-85">返回的行不包括尾随换行符。</span><span class="yiyi-st" id="yiyi-86">当用户输入EOF键序列时，会出现<a class="reference internal" href="exceptions.html#EOFError" title="EOFError"><code class="xref py py-exc docutils literal"><span class="pre">EOFError</span></code></a>。</span><span class="yiyi-st" id="yiyi-87">基本实现从<code class="docutils literal"><span class="pre">sys.stdin</span></code>；子类可以用不同的实现来代替。</span></p></dd></dl></div></div></div>