q.py

query = {
    'level': '1',
    'box.top': '2',
    'box.left': 'foo',
    'box.bottom': 'bar',
    'box.right': 'baz',
    'fox.mox.dox': '0.5',
    'fox.mox.dox': '0.5',
}


def parse_query_into(query, result):
    for key, value in query.items():
        parse_key_value_into(key, value, result)


def try_int_float(value):
    try:
        return float(value)
    except ValueError:
        try:
            return int(value)
        except ValueError:
            return value


def parse_key_value_into(key, value, result):
    value = try_int_float(value)
    if '.' not in key:
        result[key] = value
    else:
        key, _, rest = key.partition('.')
        nested = result.setdefault(key, {})
        parse_key_value_into(rest, value, nested)


def parse_query_string(query):
    result = {}
    parse_query_into(query, result)
    return result


def test_parse_query():
    result = parse_query_string(query)
    assert result == {
        'level': 1,
        'box': {'top': 2, 'left': 'foo', 'bottom': 'bar', 'right': 'baz'},
        'fox': {'mox': {'dox': 0.5}},
    }