Issue #11174: Add argparse.MetavarTypeHelpFormatter, which uses type names
for the names of optional and positional arguments in help messages.
diff --git a/Lib/argparse.py b/Lib/argparse.py
index de3cd11..2d8ed38 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -71,6 +71,7 @@
'ArgumentDefaultsHelpFormatter',
'RawDescriptionHelpFormatter',
'RawTextHelpFormatter',
+ 'MetavarTypeHelpFormatter',
'Namespace',
'Action',
'ONE_OR_MORE',
@@ -422,7 +423,8 @@
# 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:
@@ -444,7 +446,7 @@
# 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)
@@ -530,7 +532,8 @@
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:
@@ -544,7 +547,7 @@
# 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))
@@ -622,6 +625,12 @@
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.
@@ -662,6 +671,22 @@
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
# =====================
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 8d80336..5a380cb 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -3940,6 +3940,37 @@
'''
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
# =====================================