try:
    import configparser
except ImportError:
    import ConfigParser as configparser

def read_config(filename):
    '''Parse an ini file into a nested dictionary

    :param string filename: Path to the ini file to read
    :returns: A dictionary whose keys correspond to the section and
       option, joined with a dot character (.)

    For example, consider the following ini file::

        [xmen]
        storm = Ororo Monroe
        cyclops = Scott Summers

        [avengers]
        hulk = Bruce Banner
        iron_man = Tony Stark

    The resulting dictionary would look like this::

        {
            'xmen.storm': 'Ororo Monroe',
            'xmen.cyclops': 'Scott Summers',
            'avengers.hulk': 'Bruce Banner',
            'avengers.iron_man': 'Tony Stark',
        }

    Thus, the option values for any section can be obtained as follows::

        config['xmen.storm']

    This dictionary can be used to configure an :py:class:`~milla.Application`
    instance by using the ``update`` method::

        app = milla.Application(router)
        app.config.update(config)
    '''

    with open(filename) as f:
        # ConfigParser API changed in Python 3.2
        if hasattr(configparser.ConfigParser, 'read_file'):
            cparser = configparser.ConfigParser()
            cparser.read_file(f)
        else:
            cparser = configparser.SafeConfigParser()
            cparser.readfp(f)

    config = {}
    for section in cparser.sections():
        for option in cparser.options(section):
            config['.'.join((section, option))] = cparser.get(section, option)
    return config