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| author | Senthil Kumaran <senthil@uthcode.com> | 2014-09-18 13:29:21 (GMT) |
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| committer | Senthil Kumaran <senthil@uthcode.com> | 2014-09-18 13:29:21 (GMT) |
| commit | 74012c179586ec77aa3a47f03df3167a09179588 (patch) | |
| tree | bb6aae9646a87e39d4c7089c181e8cea4eddb952 /Doc/tutorial/interpreter.rst | |
| parent | cdabc372345a8fd53f50329d88dc7747a80e95d9 (diff) | |
| download | cpython-74012c179586ec77aa3a47f03df3167a09179588.zip cpython-74012c179586ec77aa3a47f03df3167a09179588.tar.gz cpython-74012c179586ec77aa3a47f03df3167a09179588.tar.bz2 | |
Issue #16827: Make Interpreter introduction section of the tutorial more
focussed and move advanced section and customization information to a separate
file called appendix.
Patch credits: Jamayla Wiley, Ya-Ting Huang and James Brewer.
Diffstat (limited to 'Doc/tutorial/interpreter.rst')
| -rw-r--r-- | Doc/tutorial/interpreter.rst | 114 |
1 files changed, 3 insertions, 111 deletions
diff --git a/Doc/tutorial/interpreter.rst b/Doc/tutorial/interpreter.rst index 5140b43..514c5f1 100644 --- a/Doc/tutorial/interpreter.rst +++ b/Doc/tutorial/interpreter.rst @@ -108,63 +108,15 @@ example, take a look at this :keyword:`if` statement:: Be careful not to fall off! +For more on interactive mode, see :ref:`tut-interac`. + + .. _tut-interp: The Interpreter and Its Environment =================================== -.. _tut-error: - -Error Handling --------------- - -When an error occurs, the interpreter prints an error message and a stack trace. -In interactive mode, it then returns to the primary prompt; when input came from -a file, it exits with a nonzero exit status after printing the stack trace. -(Exceptions handled by an :keyword:`except` clause in a :keyword:`try` statement -are not errors in this context.) Some errors are unconditionally fatal and -cause an exit with a nonzero exit; this applies to internal inconsistencies and -some cases of running out of memory. All error messages are written to the -standard error stream; normal output from executed commands is written to -standard output. - -Typing the interrupt character (usually Control-C or DEL) to the primary or -secondary prompt cancels the input and returns to the primary prompt. [#]_ -Typing an interrupt while a command is executing raises the -:exc:`KeyboardInterrupt` exception, which may be handled by a :keyword:`try` -statement. - - -.. _tut-scripts: - -Executable Python Scripts -------------------------- - -On BSD'ish Unix systems, Python scripts can be made directly executable, like -shell scripts, by putting the line :: - - #! /usr/bin/env python - -(assuming that the interpreter is on the user's :envvar:`PATH`) at the beginning -of the script and giving the file an executable mode. The ``#!`` must be the -first two characters of the file. On some platforms, this first line must end -with a Unix-style line ending (``'\n'``), not a Windows (``'\r\n'``) line -ending. Note that the hash, or pound, character, ``'#'``, is used to start a -comment in Python. - -The script can be given an executable mode, or permission, using the -:program:`chmod` command:: - - $ chmod +x myscript.py - -On Windows systems, there is no notion of an "executable mode". The Python -installer automatically associates ``.py`` files with ``python.exe`` so that -a double-click on a Python file will run it as a script. The extension can -also be ``.pyw``, in that case, the console window that normally appears is -suppressed. - - .. _tut-source-encoding: Source Code Encoding @@ -207,63 +159,3 @@ supported. To display all these characters properly, your editor must recognize that the file is UTF-8, and it must use a font that supports all the characters in the file. - -.. _tut-startup: - -The Interactive Startup File ----------------------------- - -When you use Python interactively, it is frequently handy to have some standard -commands executed every time the interpreter is started. You can do this by -setting an environment variable named :envvar:`PYTHONSTARTUP` to the name of a -file containing your start-up commands. This is similar to the :file:`.profile` -feature of the Unix shells. - -.. XXX This should probably be dumped in an appendix, since most people - don't use Python interactively in non-trivial ways. - -This file is only read in interactive sessions, not when Python reads commands -from a script, and not when :file:`/dev/tty` is given as the explicit source of -commands (which otherwise behaves like an interactive session). It is executed -in the same namespace where interactive commands are executed, so that objects -that it defines or imports can be used without qualification in the interactive -session. You can also change the prompts ``sys.ps1`` and ``sys.ps2`` in this -file. - -If you want to read an additional start-up file from the current directory, you -can program this in the global start-up file using code like ``if -os.path.isfile('.pythonrc.py'): execfile('.pythonrc.py')``. If you want to use -the startup file in a script, you must do this explicitly in the script:: - - import os - filename = os.environ.get('PYTHONSTARTUP') - if filename and os.path.isfile(filename): - execfile(filename) - - -.. _tut-customize: - -The Customization Modules -------------------------- - -Python provides two hooks to let you customize it: :mod:`sitecustomize` and -:mod:`usercustomize`. To see how it works, you need first to find the location -of your user site-packages directory. Start Python and run this code: - - >>> import site - >>> site.getusersitepackages() - '/home/user/.local/lib/python2.7/site-packages' - -Now you can create a file named :file:`usercustomize.py` in that directory and -put anything you want in it. It will affect every invocation of Python, unless -it is started with the :option:`-s` option to disable the automatic import. - -:mod:`sitecustomize` works in the same way, but is typically created by an -administrator of the computer in the global site-packages directory, and is -imported before :mod:`usercustomize`. See the documentation of the :mod:`site` -module for more details. - - -.. rubric:: Footnotes - -.. [#] A problem with the GNU Readline package may prevent this. |