#1665333: add more docs for optparse.OptionGroup.

This commit is contained in:
Georg Brandl 2011-01-02 14:23:43 +00:00
parent 00d43fd056
commit 121ff8235b
1 changed files with 99 additions and 25 deletions

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@ -61,9 +61,9 @@ and :mod:`optparse` will print out a brief summary of your script's options:
.. code-block:: text
usage: <yourscript> [options]
Usage: <yourscript> [options]
options:
Options:
-h, --help show this help message and exit
-f FILE, --file=FILE write report to FILE
-q, --quiet don't print status messages to stdout
@ -492,9 +492,9 @@ following to standard output:
.. code-block:: text
usage: <yourscript> [options] arg1 arg2
Usage: <yourscript> [options] arg1 arg2
options:
Options:
-h, --help show this help message and exit
-v, --verbose make lots of noise [default]
-q, --quiet be vewwy quiet (I'm hunting wabbits)
@ -518,7 +518,7 @@ help message:
is then printed before the detailed option help.
If you don't supply a usage string, :mod:`optparse` uses a bland but sensible
default: ``"usage: %prog [options]"``, which is fine if your script doesn't
default: ``"Usage: %prog [options]"``, which is fine if your script doesn't
take any positional arguments.
* every option defines a help string, and doesn't worry about line-wrapping---
@ -550,12 +550,33 @@ help message:
default value. If an option has no default value (or the default value is
``None``), ``%default`` expands to ``none``.
Grouping Options
++++++++++++++++
When dealing with many options, it is convenient to group these options for
better help output. An :class:`OptionParser` can contain several option groups,
each of which can contain several options.
Continuing with the parser defined above, adding an :class:`OptionGroup` to a
parser is easy::
An option group is obtained using the class :class:`OptionGroup`:
.. class:: OptionGroup(parser, title, description=None)
where
* parser is the :class:`OptionParser` instance the group will be insterted in
to
* title is the group title
* description, optional, is a long description of the group
:class:`OptionGroup` inherits from :class:`OptionContainer` (like
:class:`OptionParser`) and so the :meth:`add_option` method can be used to add
an option to the group.
Once all the options are declared, using the :class:`OptionParser` method
:meth:`add_option_group` the group is added to the previously defined parser.
Continuing with the parser defined in the previous section, adding an
:class:`OptionGroup` to a parser is easy::
group = OptionGroup(parser, "Dangerous Options",
"Caution: use these options at your own risk. "
@ -567,20 +588,73 @@ This would result in the following help output:
.. code-block:: text
usage: [options] arg1 arg2
Usage: <yourscript> [options] arg1 arg2
options:
-h, --help show this help message and exit
-v, --verbose make lots of noise [default]
-q, --quiet be vewwy quiet (I'm hunting wabbits)
-fFILE, --file=FILE write output to FILE
-mMODE, --mode=MODE interaction mode: one of 'novice', 'intermediate'
[default], 'expert'
Options:
-h, --help show this help message and exit
-v, --verbose make lots of noise [default]
-q, --quiet be vewwy quiet (I'm hunting wabbits)
-f FILE, --filename=FILE
write output to FILE
-m MODE, --mode=MODE interaction mode: novice, intermediate, or
expert [default: intermediate]
Dangerous Options:
Caution: use of these options is at your own risk. It is believed that
some of them bite.
-g Group option.
Dangerous Options:
Caution: use these options at your own risk. It is believed that some
of them bite.
-g Group option.
A bit more complete example might invole using more than one group: still
extendind the previous example::
group = OptionGroup(parser, "Dangerous Options",
"Caution: use these options at your own risk. "
"It is believed that some of them bite.")
group.add_option("-g", action="store_true", help="Group option.")
parser.add_option_group(group)
group = OptionGroup(parser, "Debug Options")
group.add_option("-d", "--debug", action="store_true",
help="Print debug information")
group.add_option("-s", "--sql", action="store_true",
help="Print all SQL statements executed")
group.add_option("-e", action="store_true", help="Print every action done")
parser.add_option_group(group)
that results in the following output:
.. code-block:: text
Usage: <yourscript> [options] arg1 arg2
Options:
-h, --help show this help message and exit
-v, --verbose make lots of noise [default]
-q, --quiet be vewwy quiet (I'm hunting wabbits)
-f FILE, --filename=FILE
write output to FILE
-m MODE, --mode=MODE interaction mode: novice, intermediate, or expert
[default: intermediate]
Dangerous Options:
Caution: use these options at your own risk. It is believed that some
of them bite.
-g Group option.
Debug Options:
-d, --debug Print debug information
-s, --sql Print all SQL statements executed
-e Print every action done
Another interesting method, in particular when working programmatically with
option groups is:
.. method:: OptionParser.get_option_group(opt_str)
Return, if defined, the :class:`OptionGroup` that has the title or the long
description equals to *opt_str*
.. _optparse-printing-version-string:
@ -652,14 +726,14 @@ Consider the first example above, where the user passes ``4x`` to an option
that takes an integer::
$ /usr/bin/foo -n 4x
usage: foo [options]
Usage: foo [options]
foo: error: option -n: invalid integer value: '4x'
Or, where the user fails to pass a value at all::
$ /usr/bin/foo -n
usage: foo [options]
Usage: foo [options]
foo: error: -n option requires an argument
@ -1161,9 +1235,9 @@ must specify for any option using that action.
.. code-block:: text
usage: foo.py [options]
Usage: foo.py [options]
options:
Options:
-h, --help Show this help message and exit
-v Be moderately verbose
--file=FILENAME Input file to read data from
@ -1358,7 +1432,7 @@ it resolves the situation by removing ``-n`` from the earlier option's list of
option strings. Now ``--dry-run`` is the only way for the user to activate
that option. If the user asks for help, the help message will reflect that::
options:
Options:
--dry-run do no harm
[...]
-n, --noisy be noisy
@ -1374,7 +1448,7 @@ existing OptionParser::
At this point, the original ``-n``/``--dry-run`` option is no longer
accessible, so :mod:`optparse` removes it, leaving this help text::
options:
Options:
[...]
-n, --noisy be noisy
--dry-run new dry-run option