From 849841ad0021e632141f9c7353bd98264b193fe2 Mon Sep 17 00:00:00 2001
From: "steven.bethard" <devnull@localhost>
Date: Mon, 13 Jul 2009 00:34:43 +0000
Subject: Allow tuples for metavars.

---
 argparse.py                 | 33 ++++++++++++++++++++-------------
 doc/source/add_argument.rst | 14 ++++++++++++++
 test/test_argparse.py       | 27 +++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 13 deletions(-)

diff --git a/argparse.py b/argparse.py
index 8ee556b..fab54e3 100644
--- a/argparse.py
+++ b/argparse.py
@@ -495,7 +495,8 @@ class HelpFormatter(object):
 
     def _format_action_invocation(self, action):
         if not action.option_strings:
-            return self._format_metavar(action, action.dest)
+            metavar, = self._metavar_formatter(action, action.dest)(1)
+            return metavar
 
         else:
             parts = []
@@ -515,30 +516,36 @@ class HelpFormatter(object):
 
             return ', '.join(parts)
 
-    def _format_metavar(self, action, default_metavar):
+    def _metavar_formatter(self, action, default_metavar):
         if action.metavar is not None:
-            name = action.metavar
+            result = action.metavar
         elif action.choices is not None:
             choice_strs = [str(choice) for choice in action.choices]
-            name = '{%s}' % ','.join(choice_strs)
+            result = '{%s}' % ','.join(choice_strs)
         else:
-            name = default_metavar
-        return name
+            result = default_metavar
+        def format(tuple_size):
+            if isinstance(result, tuple):
+                return result
+            else:
+                return (result, ) * tuple_size
+        return format
 
     def _format_args(self, action, default_metavar):
-        name = self._format_metavar(action, default_metavar)
+        get_metavar = self._metavar_formatter(action, default_metavar)
         if action.nargs is None:
-            result = name
+            result = '%s' % get_metavar(1)
         elif action.nargs == OPTIONAL:
-            result = '[%s]' % name
+            result = '[%s]' % get_metavar(1)
         elif action.nargs == ZERO_OR_MORE:
-            result = '[%s [%s ...]]' % (name, name)
+            result = '[%s [%s ...]]' % get_metavar(2)
         elif action.nargs == ONE_OR_MORE:
-            result = '%s [%s ...]' % (name, name)
+            result = '%s [%s ...]' % get_metavar(2)
         elif action.nargs is PARSER:
-            result = '%s ...' % name
+            result = '%s ...' % get_metavar(1)
         else:
-            result = ' '.join([name] * action.nargs)
+            formats = ['%s' for _ in range(action.nargs)]
+            result = ' '.join(formats) % get_metavar(action.nargs)
         return result
 
     def _expand_help(self, action):
diff --git a/doc/source/add_argument.rst b/doc/source/add_argument.rst
index 667889f..43e1b29 100644
--- a/doc/source/add_argument.rst
+++ b/doc/source/add_argument.rst
@@ -378,6 +378,20 @@ If you would like to provide a different name for your argument in help messages
 
 Note that ``metavar`` only changes the *displayed* name - the name of the attribute on the :meth:`parse_args` object is still determined by the dest_ value.
 
+Different values of ``nargs`` may cause the metavar to be used multiple times.
+If you'd like to specify a different display name for each of the arguments, you can provide a tuple to ``metavar``::
+
+  >>> parser = argparse.ArgumentParser(prog='PROG')
+  >>> parser.add_argument('-x', nargs=2)
+  >>> parser.add_argument('--foo', nargs=2, metavar=('bar', 'baz'))
+  >>> parser.print_help()
+  usage: PROG [-h] [-x X X] [--foo bar baz]
+
+  optional arguments:
+    -h, --help     show this help message and exit
+    -x X X
+    --foo bar baz
+
 
 dest
 ----
diff --git a/test/test_argparse.py b/test/test_argparse.py
index 67026d9..bd5a854 100644
--- a/test/test_argparse.py
+++ b/test/test_argparse.py
@@ -3080,6 +3080,33 @@ class TestHelpNone(HelpTestCase):
     version = ''
 
 
+class TestHelpTupleMetavar(HelpTestCase):
+    """Test specifying metavar as a tuple"""
+
+    parser_signature = Sig(prog='PROG')
+    argument_signatures = [
+        Sig('-w', help='w', nargs='+', metavar=('W1', 'W2')),
+        Sig('-x', help='x', nargs='*', metavar=('X1', 'X2')),
+        Sig('-y', help='y', nargs=3, metavar=('Y1', 'Y2', 'Y3')),
+        Sig('-z', help='z', nargs='?', metavar=('Z1', )),
+    ]
+    argument_group_signatures = []
+    usage = '''\
+        usage: PROG [-h] [-w W1 [W2 ...]] [-x [X1 [X2 ...]]] [-y Y1 Y2 Y3] \
+[-z [Z1]]
+        '''
+    help = usage + '''\
+
+        optional arguments:
+          -h, --help        show this help message and exit
+          -w W1 [W2 ...]    w
+          -x [X1 [X2 ...]]  x
+          -y Y1 Y2 Y3       y
+          -z [Z1]           z
+        '''
+    version = ''
+
+
 class TestHelpRawText(HelpTestCase):
     """Test the RawTextHelpFormatter"""
 
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