Simple lambda functions without `lambda x:` and with string conversion capability.

mini, minimal, lambda, expr, expression, simple, print, string, func, function, symbol, symbolic
pip install mini-lambda==2.2.3



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Simple lambda functions without lambda x: and with string conversion capability. Originally developed in the valid8 validation library.

This is the readme for developers. The documentation for users is available here:

Building from sources + notes on this project's design principles

This project is basically code generating code generating code :)

The following command performs the first code generation. It updates the mini_lambda/ file.

python ./code_generation/

It is based on a mako template located at code_generation/mini_lambda_template.mako.

The generated code contains functions that generate functions when called, such as:

def __gt__(self, other):
    """ Returns a new LambdaExpression performing '<r> > other' on the result <r> of this evaluator's evaluation """
    def ___gt__(input):
        # first evaluate the inner function
        r = self.evaluate(input)
        # then call the method
        return r > evaluate(other, input)

    # return a new LambdaExpression of the same type than self, with the new function as inner function
    return type(self)(___gt__)

So whenever you use the syntax provided, for example when you perform power2 = x > 2 |_, it dynamically creates a 'closure' function (here ___gt__), that will be called when you will later evaluate the expression on an input, as in power2(3).

Want to contribute ?

Contributions are welcome ! Simply fork this project on github, commit your contributions, and create pull requests.

Here is a non-exhaustive list of interesting open topics:

Running the tests

This project uses pytest.

pytest -v mini_lambda/tests/

You may need to install requirements for setup beforehand, using

pip install -r ci_tools/requirements-test.txt


This project uses setuptools_scm to synchronise the version number. Therefore the following command should be used for development snapshots as well as official releases:

python egg_info bdist_wheel rotate -m.whl -k3

You need to generate code before packaging.

You also may need to install requirements for setup beforehand, using

pip install -r ci_tools/requirements-setup.txt

Generating the documentation page

This project uses mkdocs to generate its documentation page. Therefore building a local copy of the doc page may be done using:

mkdocs build

You may need to install requirements for doc beforehand, using

pip install -r ci_tools/requirements-doc.txt

Generating the test reports

The following commands generate the html test report and the associated badge.

pytest --junitxml=junit.xml -v mini_lambda/tests/
ant -f ci_tools/generate-junit-html.xml
python ci_tools/

PyPI Releasing memo

This project is now automatically deployed to PyPI when a tag is created. Anyway, for manual deployment we can use:

twine upload dist/* -r pypitest
twine upload dist/*