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		831b6de6d7
		
			
		
	
	
	
	
		
			
			* Remove getopt and optparse deprecation notices * Add new docs sections for command line app helper libraries * Add guidance on choosing a CLI parsing library to the optparse docs * Link to the new guidance from the argparse and getopt docs * Reword intro in docs section for superseded stdlib modules * Reframe the optparse->argparse guide as a migration guide rather than as an upgrade guide --------- Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
		
			
				
	
	
		
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			65 lines
		
	
	
	
		
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			ReStructuredText
		
	
	
	
	
	
| .. currentmodule:: argparse
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| 
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| .. _upgrading-optparse-code:
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| .. _migrating-optparse-code:
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| 
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| ============================================
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| Migrating ``optparse`` code to ``argparse``
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| ============================================
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| 
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| The :mod:`argparse` module offers several higher level features not natively
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| provided by the :mod:`optparse` module, including:
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| 
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| * Handling positional arguments.
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| * Supporting subcommands.
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| * Allowing alternative option prefixes like ``+`` and ``/``.
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| * Handling zero-or-more and one-or-more style arguments.
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| * Producing more informative usage messages.
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| * Providing a much simpler interface for custom ``type`` and ``action``.
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| 
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| Originally, the :mod:`argparse` module attempted to maintain compatibility
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| with :mod:`optparse`.  However, the fundamental design differences between
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| supporting declarative command line option processing (while leaving positional
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| argument processing to application code), and supporting both named options
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| and positional arguments in the declarative interface mean that the
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| API has diverged from that of ``optparse`` over time.
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| 
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| As described in :ref:`choosing-an-argument-parser`, applications that are
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| currently using :mod:`optparse` and are happy with the way it works can
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| just continue to use ``optparse``.
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| 
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| Application developers that are considering migrating should also review
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| the list of intrinsic behavioural differences described in that section
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| before deciding whether or not migration is desirable.
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| 
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| For applications that do choose to migrate from :mod:`optparse` to :mod:`argparse`,
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| the following suggestions should be helpful:
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| 
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| * Replace all :meth:`optparse.OptionParser.add_option` calls with
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|   :meth:`ArgumentParser.add_argument` calls.
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| 
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| * Replace ``(options, args) = parser.parse_args()`` with ``args =
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|   parser.parse_args()`` and add additional :meth:`ArgumentParser.add_argument`
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|   calls for the positional arguments. Keep in mind that what was previously
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|   called ``options``, now in the :mod:`argparse` context is called ``args``.
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| 
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| * Replace :meth:`optparse.OptionParser.disable_interspersed_args`
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|   by using :meth:`~ArgumentParser.parse_intermixed_args` instead of
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|   :meth:`~ArgumentParser.parse_args`.
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| 
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| * Replace callback actions and the ``callback_*`` keyword arguments with
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|   ``type`` or ``action`` arguments.
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| 
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| * Replace string names for ``type`` keyword arguments with the corresponding
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|   type objects (e.g. int, float, complex, etc).
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| 
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| * Replace :class:`optparse.Values` with :class:`Namespace` and
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|   :exc:`optparse.OptionError` and :exc:`optparse.OptionValueError` with
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|   :exc:`ArgumentError`.
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| 
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| * Replace strings with implicit arguments such as ``%default`` or ``%prog`` with
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|   the standard Python syntax to use dictionaries to format strings, that is,
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|   ``%(default)s`` and ``%(prog)s``.
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| 
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| * Replace the OptionParser constructor ``version`` argument with a call to
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|   ``parser.add_argument('--version', action='version', version='<the version>')``.
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