Evaluate expressions in dict/json objects
Project description
dicteval
========
Library to evaluate expressions in dict/json objects.
Requirements
------------
* Python 3.6+
Basic Usage
-----------
Module ``dicteval`` will evaluate basic types with no modifications but it will
evaluate dicts (or json objects) containing keys started with ``=`` (equal)
symbol as an expression:
>>> from dicteval import dicteval
>>> dicteval(3)
3
>>> dicteval([3, 5])
[3, 5]
>>> dicteval((5, 3))
[5, 3]
>>> dicteval({"=sum": [3, 5]})
8
>>> dicteval({"=": 5}) # = symbol alone is a 'nop' function
5
You can provide a dictionary with context to be used during evaluation process.
>>> dicteval({"=": "!{var}"}, context={"var": 1.0})
1.0
You can also wrap your string content with ``@{}`` to force a Python ``eval()``
with the context provided:
>>> dicteval({"=sum": [3, "@{var + 2}"]}, context={"var": 3})
8
.. warning::
This functionality will be removed (or changed) in future releases for
security reasons.
Functions
---------
You can use the following builtin functions in your expressions:
Function ``=any``
'''''''''''''''''
Returns ``True`` if any element of sequence is true.
>>> dicteval({"=any": [1, 2, 3]})
True
>>> dicteval({"=any": [0, 0]})
False
Function ``=eq``
''''''''''''''''
Returns ``True`` if all elements of sequence are equals:
>>> dicteval({"=eq": [1, 1, 1, 1]})
True
Function ``=if``
''''''''''''''''
Evaluates condition and returns first value if true, otherwise, returns second value.
If no false value is supplied, it is assumed to be ``None``.
>>> dicteval({"=if": [{"=": "@{var > 5}"}, "yes", "no"]}, context={"var": 6})
'yes'
>>> dicteval({"=if": [{"=": "@{var > 5}"}, "yes", "no"]}, context={"var": 4})
'no'
>>> dicteval({"=if": [{"=": "@{var > 5}"}, "yes"]}, context={"var": 4})
Function ``=neq``
''''''''''''''''
Returns ``True`` if elements of sequence are different:
>>> dicteval({"=neq": [1, 1, 1, 5]})
True
Function ``=`` (or ``nop``)
'''''''''''''''''''''''''''
Returns the same values passed as arguments:
>>> dicteval({"=": [1, 2, 3, 4]})
[1, 2, 3, 4]
>>> dicteval({"=nop": "spam"})
'spam'
Function ``=not``
''''''''''''''''
Returns the boolean inverse of argument:
>>> dicteval({"=not": False})
True
>>> dicteval({"=not": True})
False
>>> dicteval({"=not": None})
True
>>> dicteval({"=not": "XYZ"})
False
Function ``=sum``
'''''''''''''''''
Returns a number with the sum of arguments:
>>> dicteval({"=sum": [3, 5]})
8
Function ``=mul``
'''''''''''''''''
Returns a number with the product of arguments:
>>> dicteval({"=mul": [3, 5]})
15
Function ``=all``
'''''''''''''''''
Return True if all elements of the iterable are true (or if the iterable is empty)
>>> dicteval({"=all": (True, False)})
False
>>> dicteval({"=all": (True, True)})
True
Function ``=divmod``
'''''''''''''''''
Returns a tuple containing the quotient and remainder after division:
>>> dicteval({"=divmod": [8,3]})
(2, 2)
>>> dicteval({"=divmod": [7.5,2.5]})
(3.0, 0.0)
Function ``=zip``
'''''''''''''''''
Return list of aggregate tuples constructed from elements of multiple iterables.
>>> dicteval({"=zip": [[1, 2, 3], [4, 5], [6, 7, 8, 9]]})
[(1, 4, 6), (2, 5, 7)]
To Do
-----
- Add more functions to the builtin language
Contribute
----------
To contribute to `dicteval`:
1. Clone this repository and `cd` into it
2. Install dev dependencies with [pipenv](https://github.com/pypa/pipenv)
```bash
pipenv install --dev
```
3. Create a branch, like `git checkout -b [feature_name]`
4. Git commit changes
5. Pull request
License
-------
This software is licensed under MIT license.
Project details
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
dicteval-0.0.5.tar.gz
(4.9 kB
view hashes)