Linked Dictionary

Advanced python dictionary(hash-table), which can link it-self keys and make calculations into the keys of the dict

Installation

Use the package manager pip to install foobar.

pip install linked-dict

Usage

The syntax of expressions:

{'key' : '...$(expression)$...'}

Initialization:

from linked_dict import LinkedDict
from json import dumps

dictionary = LinkedDict({})  # {} - your dict

Examples:

Simple link:

example = LinkedDict(
    {
        'a': 5,
        'b': '$(a)$'
    }
)

print(dumps(example))

    {
       'a': 5,
       'b': 5
    }

Expression with one key. As you can see now I added a space outside this expression, and the final value is string:

example = LinkedDict(
    {
        'a': 5,
        'b': '$(a * 2)$ ' # here with a space
    }
)

print(dumps(example))

    {
       'a': 5,
       'b': '10 '
    }

Link other expressions:

example = LinkedDict(
    {
        'a': 5,
        'b': 100,
        'c': '$(b + d)$',
        'd': '$(b + a)$'
    }
)

print(dumps(example))

    {
        'a': 5,
        'b': 100,
        'c': 205,
        'd': 105
    }

Using all built-in types:

example = LinkedDict(
    {
        'a': ['one_item'],
        'b': '$(a + ["another_item"])$'
    }
)

print(dumps(example))

    {
        'a': ['one_item'],
        'b': ['one_item', 'another_item']
    }

Using your own functions into expressions:

some_func = lambda arg: arg + 1

example = LinkedDict(
    {
        'a': 5,
        'b': '$(some_func(a))$'
    },
    loc=locals(), # to be able to use your functions
    glob=globals() # to be able to use your functions
) 

print(dumps(example))

    {
       'a': 5,
       'b': 5
    }

Changing:

When you change a value, all values that link it change their values too. But links work only in one direction

example = LinkedDict(
    {
        'a': 5,
        'b': '$(a)$'
    }
)
print(example) 
# >>> {'a': 5, 'b': 5}
example['a'] = 'another_val'
print(example)
# >>> {'a': 'another_val', 'b': 'another_val'}
example['b'] = '4'
print(example) 
# >>> {'a': 'another_val', 'b': 4}

# !!! 'b' links 'a', but 'a' doesn't link 'b'

Warning:

1. Keys of your dict must be only strings

{5: 'abc', True: []} # is prohibited
{'5': 'abc', 'True': []} # is allowed

2. Don't make loops of links. Dictionary is protected of this, but you will get the Error

Contributing:

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT