.. -*- mode: rst -*-

========
 Opster
========

Opster is a command line options parser, intended to make writing command line
applications easy and painless. It uses built-in Python types (lists,
dictionaries, etc) to define options, which makes configuration clear and
concise. Additionally it contains possibility to handle subcommands (i.e.
``hg commit`` or ``svn update``).

Quick example
-------------

That's an example of an option definition::

  import sys
  from opster import command

  @command(usage='%name [-n] MESSAGE')
  def main(message,
           no_newline=('n', False, 'don\'t print a newline')):
      'Simple echo program'
      sys.stdout.write(message)
      if not no_newline:
          sys.stdout.write('\n')

  if __name__ == '__main__':
      main()

Running this program will print the help::

  echo.py [-n] MESSAGE

  Simple echo program

  options:

   -n --no-newline  don't print a newline
   -h --help        show help

As you can see, here we have defined option to not print newline: keyword
argument name is a long name for option, default value is a 3-tuple, containing
short name for an option (can be empty), default value (on base of which
processing is applied - `see description`_) and a help string.

Underscores in long names are converted into dashes.

If you are calling a command with option using long name, you can supply it
partially. In this case it could look like ``./echo.py --nonew``. This is also
true for subcommands: read about them and everything else you'd like to know in
`documentation`_.

.. _documentation: http://hg.piranha.org.ua/opster/docs/
.. _see description: http://hg.piranha.org.ua/opster/docs/overview.html