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Diffstat (limited to 'Doc/library/idle.rst')
| -rw-r--r-- | Doc/library/idle.rst | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/Doc/library/idle.rst b/Doc/library/idle.rst index fa58e2d..f353fbc 100644 --- a/Doc/library/idle.rst +++ b/Doc/library/idle.rst @@ -671,15 +671,23 @@ When a program outputs text, the result is determined by the corresponding output device. When IDLE executes user code, ``sys.stdout`` and ``sys.stderr`` 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. +are programmed additions. Where it matters, Shell is designed for development +rather than production runs. + +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. 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 ``repr()`` function, which is used for -interactive echo of expression values, replaces control characters -with escape codes before they are output. +text to appear on a new line, but other control characters are either +replaced with a box or deleted. However, ``repr()``, 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. Normal and error output are generally kept separate (on separate lines) from code input and each other. They each get different highlight colors. |