for the names of optional and positional arguments in help messages.
^^^^^^^^^^^^^^^
:class:`ArgumentParser` objects allow the help formatting to be customized by
-specifying an alternate formatting class. Currently, there are three such
-classes: :class:`argparse.RawDescriptionHelpFormatter`,
-:class:`argparse.RawTextHelpFormatter` and
-:class:`argparse.ArgumentDefaultsHelpFormatter`. The first two allow more
-control over how textual descriptions are displayed, while the last
-automatically adds information about argument default values.
+specifying an alternate formatting class.
+:class:`RawDescriptionHelpFormatter` and :class:`RawTextHelpFormatter` give
+more control over how textual descriptions are displayed.
By default, :class:`ArgumentParser` objects line-wrap the description_ and
epilog_ texts in command-line help messages::
likewise for this epilog whose whitespace will be cleaned up and whose words
will be wrapped across a couple lines
-Passing :class:`argparse.RawDescriptionHelpFormatter` as ``formatter_class=``
+Passing :class:`RawDescriptionHelpFormatter` as ``formatter_class=``
indicates that description_ and epilog_ are already correctly formatted and
should not be line-wrapped::
optional arguments:
-h, --help show this help message and exit
-:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text
+:class:`RawTextHelpFormatter` maintains whitespace for all sorts of help text,
including argument descriptions.
-The other formatter class available, :class:`ArgumentDefaultsHelpFormatter`,
-will add information about the default value of each of the arguments::
+:class:`ArgumentDefaultsHelpFormatter` automatically adds information about
+default values to each of the argument help messages::
>>> parser = argparse.ArgumentParser(
... prog='PROG',
-h, --help show this help message and exit
--foo FOO FOO! (default: 42)
+:class:`MetavarTypeHelpFormatter` uses the name of the type_ argument for each
+argument as as the display name for its values (rather than using the dest_
+as the regular formatter does)::
+
+ >>> parser = argparse.ArgumentParser(
+ ... prog='PROG',
+ ... formatter_class=argparse.MetavarTypeHelpFormatter)
+ >>> parser.add_argument('--foo', type=int)
+ >>> parser.add_argument('bar', type=float)
+ >>> parser.print_help()
+ usage: PROG [-h] [--foo int] float
+
+ positional arguments:
+ float
+
+ optional arguments:
+ -h, --help show this help message and exit
+ --foo int
+
conflict_handler
^^^^^^^^^^^^^^^^
'ArgumentDefaultsHelpFormatter',
'RawDescriptionHelpFormatter',
'RawTextHelpFormatter',
+ 'MetavarTypeHelpFormatter',
'Namespace',
'Action',
'ONE_OR_MORE',
# produce all arg strings
elif not action.option_strings:
- part = self._format_args(action, action.dest)
+ default = self._get_default_metavar_for_positional(action)
+ part = self._format_args(action, default)
# if it's in a group, strip the outer []
if action in group_actions:
# if the Optional takes a value, format is:
# -s ARGS or --long ARGS
else:
- default = action.dest.upper()
+ default = self._get_default_metavar_for_optional(action)
args_string = self._format_args(action, default)
part = '%s %s' % (option_string, args_string)
def _format_action_invocation(self, action):
if not action.option_strings:
- metavar, = self._metavar_formatter(action, action.dest)(1)
+ default = self._get_default_metavar_for_positional(action)
+ metavar, = self._metavar_formatter(action, default)(1)
return metavar
else:
# if the Optional takes a value, format is:
# -s ARGS, --long ARGS
else:
- default = action.dest.upper()
+ default = self._get_default_metavar_for_optional(action)
args_string = self._format_args(action, default)
for option_string in action.option_strings:
parts.append('%s %s' % (option_string, args_string))
def _get_help_string(self, action):
return action.help
+ def _get_default_metavar_for_optional(self, action):
+ return action.dest.upper()
+
+ def _get_default_metavar_for_positional(self, action):
+ return action.dest
+
class RawDescriptionHelpFormatter(HelpFormatter):
"""Help message formatter which retains any formatting in descriptions.
return help
+class MetavarTypeHelpFormatter(HelpFormatter):
+ """Help message formatter which uses the argument 'type' as the default
+ metavar value (instead of the argument 'dest')
+
+ Only the name of this class is considered a public API. All the methods
+ provided by the class are considered an implementation detail.
+ """
+
+ def _get_default_metavar_for_optional(self, action):
+ return action.type.__name__
+
+ def _get_default_metavar_for_positional(self, action):
+ return action.type.__name__
+
+
+
# =====================
# Options and Arguments
# =====================
'''
version = ''
+
+class TestHelpMetavarTypeFormatter(HelpTestCase):
+ """"""
+
+ def custom_type(string):
+ return string
+
+ parser_signature = Sig(prog='PROG', description='description',
+ formatter_class=argparse.MetavarTypeHelpFormatter)
+ argument_signatures = [Sig('a', type=int),
+ Sig('-b', type=custom_type),
+ Sig('-c', type=float, metavar='SOME FLOAT')]
+ argument_group_signatures = []
+ usage = '''\
+ usage: PROG [-h] [-b custom_type] [-c SOME FLOAT] int
+ '''
+ help = usage + '''\
+
+ description
+
+ positional arguments:
+ int
+
+ optional arguments:
+ -h, --help show this help message and exit
+ -b custom_type
+ -c SOME FLOAT
+ '''
+ version = ''
+
+
# =====================================
# Optional/Positional constructor tests
# =====================================
- Issue #11388: Added a clear() method to MutableSequence
+- Issue #11174: Add argparse.MetavarTypeHelpFormatter, which uses type names
+ for the names of optional and positional arguments in help messages.
+
Build
-----
projects / python / commitdiff