parsial 0.1.0
Python library that transforms any string parser into a parser that skips portions of the input that contain syntax errors.
License: MIT
Requires Python: >=3.7

=======
parsial
=======

Python library that transforms any string parser into a parser that skips portions of the input that contain syntax errors.

|pypi| |readthedocs| |actions| |coveralls|

.. |pypi| image:: https://badge.fury.io/py/parsial.svg#
   :target: https://badge.fury.io/py/parsial
   :alt: PyPI version and link.

.. |readthedocs| image:: https://readthedocs.org/projects/parsial/badge/?version=latest
   :target: https://parsial.readthedocs.io/en/latest/?badge=latest
   :alt: Read the Docs documentation status.

.. |actions| image:: https://github.com/reity/parsial/workflows/lint-test-cover-docs/badge.svg#
   :target: https://github.com/reity/parsial/actions/workflows/lint-test-cover-docs.yml
   :alt: GitHub Actions status.

.. |coveralls| image:: https://coveralls.io/repos/github/reity/parsial/badge.svg?branch=main
   :target: https://coveralls.io/github/reity/parsial?branch=main
   :alt: Coveralls test coverage summary.

Installation and Usage
----------------------
This library is available as a `package on PyPI <https://pypi.org/project/parsial>`__:

.. code-block:: bash

    python -m pip install parsial

The library can be imported in the usual way:

.. code-block:: python

    from parsial import parsial

Example
^^^^^^^

.. |parsial| replace:: ``parsial``
.. _parsial: https://parsial.readthedocs.io/en/0.1.0/_source/parsial.html#parsial.parsial.parsial

The |parsial|_ function accepts a parsing function (that takes a string input) and returns a new parsing function. This new function attempts to parse an input string using the original parsing function *even if parsing errors occur*. This is accomplished by selectively removing portions of the input that cause errors:

.. code-block:: python

    >>> lines = [
    ...     'x = 123',
    ...     'y =',
    ...     'print(x)',
    ...     'z = x +',
    ...     'print(2 * x)'
    ... ]
    >>> import ast
    >>> parser = parsial(ast.parse)
    >>> (a, slices) = parser('\\n'.join(lines))
    >>> exec(compile(a, '', 'exec'))
    123
    246

.. |slice| replace:: ``slice``
.. _slice: https://docs.python.org/3/library/functions.html#slice

In addition to returning the result, the new function also returns a list of |slice|_ instances (one for each line found in the input string):

.. code-block:: python

    >>> for s in slices:
    ...     print(s)
    slice(0, 7, None)
    slice(0, 0, None)
    slice(0, 8, None)
    slice(0, 0, None)
    slice(0, 12, None)
    
Each |slice|_ instance indicates what portion of the corresponding line in the input was included in the successful parsing attempt:

.. code-block:: python

    >>> [l[s] for (l, s) in zip(lines, slices)]
    ['x = 123', '', 'print(x)', '', 'print(2 * x)']

Development
-----------
All installation and development dependencies are fully specified in ``pyproject.toml``. The ``project.optional-dependencies`` object is used to `specify optional requirements <https://peps.python.org/pep-0621>`__ for various development tasks. This makes it possible to specify additional options (such as ``docs``, ``lint``, and so on) when performing installation using `pip <https://pypi.org/project/pip>`__:

.. code-block:: bash

    python -m pip install .[docs,lint]

Documentation
^^^^^^^^^^^^^
The documentation can be generated automatically from the source files using `Sphinx <https://www.sphinx-doc.org>`__:

.. code-block:: bash

    python -m pip install .[docs]
    cd docs
    sphinx-apidoc -f -E --templatedir=_templates -o _source .. && make html

Testing and Conventions
^^^^^^^^^^^^^^^^^^^^^^^
All unit tests are executed and their coverage is measured when using `pytest <https://docs.pytest.org>`__ (see the ``pyproject.toml`` file for configuration details):

.. code-block:: bash

    python -m pip install .[test]
    python -m pytest

Alternatively, all unit tests are included in the module itself and can be executed using `doctest <https://docs.python.org/3/library/doctest.html>`__:

.. code-block:: bash

    python src/parsial/parsial.py -v

Style conventions are enforced using `Pylint <https://pylint.readthedocs.io>`__:

.. code-block:: bash

    python -m pip install .[lint]
    python -m pylint src/parsial

Contributions
^^^^^^^^^^^^^
In order to contribute to the source code, open an issue or submit a pull request on the `GitHub page <https://github.com/reity/parsial>`__ 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 <https://semver.org/#semantic-versioning-200>`__.

Publishing
^^^^^^^^^^
This library can be published as a `package on PyPI <https://pypi.org/project/parsial>`__ by a package maintainer. First, install the dependencies required for packaging and publishing:

.. code-block:: bash

    python -m pip install .[publish]

Ensure that the correct version number appears in ``pyproject.toml``, and that any links in this README document to the Read the Docs documentation of this package (or its dependencies) have appropriate version numbers. Also ensure that the Read the Docs project for this library has an `automation rule <https://docs.readthedocs.io/en/stable/automation-rules.html>`__ that activates and sets as the default all tagged versions. Create and push a tag for this version (replacing ``?.?.?`` with the version number):

.. code-block:: bash

    git tag ?.?.?
    git push origin ?.?.?

Remove any old build/distribution files. Then, package the source into a distribution archive:

.. code-block:: bash

    rm -rf build dist src/*.egg-info
    python -m build --sdist --wheel .

Finally, upload the package distribution archive to `PyPI <https://pypi.org>`__:

.. code-block:: bash

    python -m twine upload dist/*