Expand Up @@ -648,14 +648,21 @@ <h3>User output in Shell<a class="headerlink" href="#user-output-in-shell" title corresponding output device. When IDLE executes user code, <code class="docutils literal notranslate"><span class="pre">sys.stdout</span></code> and <code class="docutils literal notranslate"><span class="pre">sys.stderr</span></code> are connected to the display area of IDLE’s Shell. Some of its features are inherited from the underlying Tk Text widget. Others are programmed additions.</p> are programmed additions. Where it matters, Shell is designed for development rather than production runs.</p> <p>For instance, Shell never throws away output. A program that sends unlimited output to Shell will eventually fill memory, resulting in a memory error. In contrast, some system text windows only keep the last n lines of output. A Windows console, for instance, keeps a user-settable 1 to 9999 lines, with 300 the default.</p> <p>Text widgets display a subset of Unicode, the Basic Multilingual Plane (BMP). Which characters get a proper glyph instead of a replacement box depends on the operating system and installed fonts. Newline characters cause following text to appear on a new line, but other control characters are replaced with a box. But note that the <code class="docutils literal notranslate"><span class="pre">repr()</span></code> function, which is used for interactive echo of expression values, replaces control characters with escape codes before they are output.</p> text to appear on a new line, but other control characters are either replaced with a box or deleted. However, <code class="docutils literal notranslate"><span class="pre">repr()</span></code>, which is used for interactive echo of expression values, replaces control characters, some BMP codepoints, and all non-BMP characters with escape codes before they are output.</p> <p>Normal and error output are generally kept separate (on separate lines) from code input and each other. They each get different highlight colors.</p> <p>For SyntaxError tracebacks, the normal ‘^’ marking where the error was Expand Down