Dynamic Spread-dot Operator in Python

spread.py

'''
    This function allow you to describe a "path" on the iterator (itr)
    and then create a generator that yields all elements that match
    the path. You can use the token "[*]" do describe an iteration over
    the list.
    
    Example:
    itr = {"foo": {
            "bar": ["baz", "foz"]
        }}
    path = "foo.bar"
    
    it will yield:
    - ["baz", "foz"]
    (1 item, the list)
    
    BUT, for the same itr, if you have the path = "foo.bar[*]", it will yield:
    - "baz"
    - "foz"
    (2 items, it iterates over the list)
'''

# requirements.txt must include
# python-box>=3.0.1

def spread_generator(path: str, itr):
    if not path:
        if itr:
            yield itr
        raise StopIteration

    itr = Box(itr)
    path_list = re.split(r'(\[\*\]\.?)', path, maxsplit=1)
    path_list = [p for p in path_list if p]
    path_0 = path_list.pop(0)
    tmp = eval(f"itr.{path_0}")
    if not path_list:
        yield tmp
    else:
        path_list.pop(0)  # Remove the chunck "[*]"
        if isinstance(tmp, Box):
            tmp = tmp.to_dict().values()
        elif isinstance(tmp, BoxList):
            tmp = tmp.to_list()
        new_path = path_list[0] if path_list else None
        yield from chain.from_iterable(
            map(lambda x: spread_generator(new_path, x), tmp)
        )
        
        
'''
    An extended example:
    
    Given
    itr = {"foo": [
            {"bar": ["bazz", "fazz"]},
            {"bar": ["bizz", "fizz"]},
            {"bar": ["buzz", "fuzz"]},
        ]
    }
    
    ===== example 1 =====
    path = "foo[*].bar"
    result:
    - ["bazz", "fazz"]
    - ["bizz", "fizz"]
    - ["buzz", "fuzz"]
    (3 items)
    
    ===== example 2 =====
    path = "foo[*].bar[*]"
    result:
    - "bazz"
    - "fazz"
    - "bizz"
    - "fizz"
    - "buzz"
    - "fuzz"
    (6 items)
    
    ===== example 3 =====
    path = "foo[:3].bar"  # you can use the list syntax from python
    result:
    - ["bazz", "fazz"]
    - ["bizz", "fizz"]
    (2 items)
    
    ===== example 4 =====
    path = "foo[*].bar[0]"
    result:
    - "bazz"
    - "bizz"
    - "buzz"
    (3 items)
'''