Nested Dictionary Comprehensions

gistfile1.py

def class_from_xml(struct_layout):
    """Define a new class based on the given struct layout defined in xml.
    """
    # { field_name => ObservableField_constructor_params }
    field_params = {
        field.attrib['name']: {
            'field_type': field.tag,
            'offset': int(field.attrib.get('offset'), 0),
            'length': int(field.attrib.get('length', '0'), 0),
            'reverse': field.attrib.get('reverse', 'false') == 'true',
            'maxlength': int(field.attrib.get('maxlength', '0'), 0),
            'options': { opt.attrib['value']: opt.attrib['name'] for opt in field.iter('option') },
            'reflexive_class': class_from_xml(field) if field.tag == 'reflexive' else None,
        }
        for field in struct_layout
    }

    class Foo(object):
        def __init__(self, extra_param):
            for name in field_params:
                setattr(self, name, make_observable_field(extra_param, field_params[name]))
    
    return Foo