lion 0.1.0

.. sourcecode :: python

Lion is a very flexible yet fast library for mapping objects to
dictionaries. It uses a declarative API and supports a query language
similar to GraphQL. Unlike other serialization libraries it also
allows to skip entire fields instead of having a ``null`` value
in the dictionary.

It is inspired by libraries like serpy_, marshmallow_,
`Django REST Framework`_ and Kim_.

Example::

import lion

class UserMapper(lion.Mapper):
id = lion.UUIDField()
email = lion.StrField(condition=lion.skip_empty)
first_name = lion.StrField()
last_name = lion.StrField()

user = User(
id=UUID('ad94d0e8-2526-4d9b-ad76-0fbffcf41033'),
email='john.doe@example.com',
first_name='John',
last_name='Doe'
)

# Dump all fields to a dictionary
assert UserMapper().dump(user) == {
'id': 'ad94d0e8-2526-4d9b-ad76-0fbffcf41033',
'email': 'john.doe@example.com',
'first_name': 'John',
'last_name': 'Doe'
}

# Dump a subset of fields
assert UserMapper('{id,email}').dump(user) == {
'id': 'ad94d0e8-2526-4d9b-ad76-0fbffcf41033',
'email': 'john.doe@example.com',
'first_name': 'John',
'last_name': 'Doe'
}

The query language also supports subfields::

UserMapper('{id,email,groups{id,name}}).dump(user)

The performance is somewhat slower than serpy_ but still far ahead of
marshmallow_ and `Django REST Framework`_

Right now only ``dumping`` (aka. serialization, marshalling) is supported
but future versions will also introduce ``loading`` (aka. deserialization,
unmarshalling) of data.

.. _serpy: https://pypi.python.org/pypi/serpy
.. _marshmallow: https://pypi.python.org/pypi/marshmallow/
.. _Kim: https://pypi.python.org/pypi/py-kim/1.2.0
.. _`Django REST Framework`: https://pypi.python.org/pypi/djangorestframework