[Python-checkins] cpython (2.7): Issue #19814: Clarify argparse's docs w.r.t prefix matching

Mon Dec 2 14:53:37 CET 2013

http://hg.python.org/cpython/rev/181ced5bf0be
changeset: 87704:181ced5bf0be
branch: 2.7
parent: 87680:02d186e3af09
user: Eli Bendersky <eliben at gmail.com>
date: Mon Dec 02 05:53:35 2013 -0800
summary:
 Issue #19814: Clarify argparse's docs w.r.t prefix matching
files:
 Doc/library/argparse.rst | 14 +++++++++++---
 1 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/Doc/library/argparse.rst b/Doc/library/argparse.rst
--- a/Doc/library/argparse.rst
+++ b/Doc/library/argparse.rst
@@ -1351,12 +1351,14 @@
 >>> parser.parse_args(['--', '-f'])
 Namespace(foo='-f', one=None)
 
+.. _prefix-matching:
 
-Argument abbreviations
-^^^^^^^^^^^^^^^^^^^^^^
+Argument abbreviations (prefix matching)
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The :meth:`~ArgumentParser.parse_args` method allows long options to be
-abbreviated if the abbreviation is unambiguous::
+abbreviated to a prefix, if the abbreviation is unambiguous (the prefix matches
+a unique option)::
 
 >>> parser = argparse.ArgumentParser(prog='PROG')
 >>> parser.add_argument('-bacon')
@@ -1822,6 +1824,12 @@
 >>> parser.parse_known_args(['--foo', '--badger', 'BAR', 'spam'])
 (Namespace(bar='BAR', foo=True), ['--badger', 'spam'])
 
+.. warning::
+ :ref:`Prefix matching <prefix-matching>` rules apply to
+ :meth:`parse_known_args`. The parser may consume an option even if it's just
+ a prefix of one of its known options, instead of leaving it in the remaining
+ arguments list.
+
 
 Customizing file parsing
 ^^^^^^^^^^^^^^^^^^^^^^^^
-- 
Repository URL: http://hg.python.org/cpython
