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-rw-r--r--Doc/library/argparse.rst31
1 files changed, 25 insertions, 6 deletions
diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
index 88270edf89..7c7319ef6f 100644
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -362,16 +362,16 @@ formatter_class
^^^^^^^^^^^^^^^
:class:`ArgumentParser` objects allow the help formatting to be customized by
-specifying an alternate formatting class. Currently, there are three such
+specifying an alternate formatting class. Currently, there are four such
classes:
.. class:: RawDescriptionHelpFormatter
RawTextHelpFormatter
ArgumentDefaultsHelpFormatter
+ MetavarTypeHelpFormatter
-The first two allow more control over how textual descriptions are displayed,
-while the last automatically adds information about argument default values.
-
+: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::
@@ -424,8 +424,8 @@ should not be line-wrapped::
: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',
@@ -442,6 +442,25 @@ will add information about the default value of each of the arguments::
-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 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
^^^^^^^^^^^^^^^^