gistfile1.pyw

import types

class Column(object):
    def __init__(self, name):
        self._name = name

    def __add__(self, other):
        return {self._name: {'$inc': other}}

    def __eq__(self, other):
        return {self._name: other}

    def in_(self, *vals):
        return {self._name: {'$in': vals}}

class Query(object):
    def __init__(self, *args, **kwargs):
        self._spec = {}
        
    def filter(self, *args):
        for arg in args:
            for k, v in arg.iteritems():
                if k in self._spec and type(v) is types.DictType\
                    and type(self._spec[k]) is types.DictType:
                        
                    self._spec[k].update(v)
                else:
                    self._spec[k] = v

        return self

    def delete(self):
        print 'deleted %s' % self.__repr__()

    def __repr__(self):
        return self._spec.__repr__()

class User(object):
    username = Column('username')
    friends = Column('friends')

Query(User).filter(User.friends.in_(5, 2, 3, 4)).filter(User.username == 'stanislav').delete()

# prints
# deleted {'username': 'stanislav', 'friends': {'$in': (5, 2, 3, 4)}}