logical 0.4.0

Callable subclass of the tuple type for representing logical operators/connectives based on their truth tables.

Callable subclass of the tuple type for representing logical operators/connectives based on their truth tables.

Package Installation and Usage

The package is available on PyPI:

python -m pip install logical

The library can be imported in the usual ways:

import logical
from logical import *

Each instance of the logical class (derived from the tuple class) represents a boolean function that accepts n inputs by specifying its output values across all possible inputs. In other words, an instance represents the output column of a truth table for a function (under the assumption that the input vectors to which each output value corresponds are sorted in ascending order). Thus, each instance representing a function that accepts n inputs must have length 2**n.

For example, consider the truth table below for a boolean function f that accepts three inputs:

x	y	z	f (x, y, z)
0	0	0	1
0	0	1	0
0	1	0	1
0	1	1	0
1	0	0	0
1	0	1	1
1	1	0	1
1	1	1	0

Notice that the input vectors (i.e., the left-most three column values in each row) are sorted in ascending order from top to bottom. If we always assume this order for input vectors, the entire function f can be represented using the right-most column. For the example function f defined by the table above, this can be done in the manner illustrated below:

>>> from logical import *
>>> f = logical((1, 0, 1, 0, 0, 1, 1, 0))

It is then possible to apply the instance f defined above to any three-component input vector:

>>> f(0, 1, 1)
0
>>> f(1, 1, 0)
1

Pre-defined instances are provided for all unary and binary boolean functions. These are available both as constants and as attributes of the logical class:

>>> logical.xor_(1, 0)
1
>>> and_(1, 0)
0

The constants unary and binary are also defined. Each is a set containing exactly those instances of logical that represent functions having that arity:

>>> unary
{(0, 0), (1, 0), (1, 1), (0, 1)}
>>> len(binary)
16

Documentation

The documentation can be generated automatically from the source files using Sphinx:

cd docs
python -m pip install -r requirements.txt
sphinx-apidoc -f -E --templatedir=_templates -o _source .. ../setup.py && make html

Testing and Conventions

All unit tests are executed and their coverage is measured when using pytest (see setup.cfg for configuration details):

python -m pip install pytest pytest-cov
python -m pytest

Alternatively, all unit tests are included in the module itself and can be executed using doctest:

python logical/logical.py -v

Style conventions are enforced using Pylint:

python -m pip install pylint
python -m pylint logical

Contributions

In order to contribute to the source code, open an issue or submit a pull request on the GitHub page for this library.

Versioning

The version number format for this library and the changes to the library associated with version number increments conform with Semantic Versioning 2.0.0.

Publishing

This library can be published as a package on PyPI by a package maintainer. Install the wheel package, remove any old build/distribution files, and package the source into a distribution archive:

python -m pip install wheel
rm -rf dist *.egg-info
python setup.py sdist bdist_wheel

Next, install the twine package and upload the package distribution archive to PyPI:

python -m pip install twine
python -m twine upload dist/*