Hurler

A decorator based filtering mechanism of function calls. Hurler allows you to decorate a function to prevent calling of the function unless all conditions pass.

Example

A simple example showing how our printer function is only called when the condition number < 5 is True.

from hurler import filter_simple

@filter_simple
def lower_than_five(number):
    return number < 5

@lower_than_five
def printer(number):
    print("Received: %d" % number)

And now we can call printer with our filter in place.

>>> printer(0)      # 0 < 5 == True
Received: 0
>>> printer(10)     # 10 < 5 == False, `printer` doesn't get called.
>>> printer(100)    # 100 < 5 == False
>>> printer(4)      # 4 < 5 == True
Received: 4

For examples of the more advanced filter function see the test_example.py file in the hurler package. This file is part of the testing and seconds as a good example for usage.

Why?

Hurler was originally created for inclusion in an IRC library, it fills the role of accompanying the event callback system.

With hurler we could keep the basic callback system simple, it only requires registering a function with an event_name.

Callbacks for say, a specific message string or nickname is now done through hurler filters. Instead of repeating ourself in every callback that required it. An alternative to hurler is creating different register methods that take extra arguments to determine your filter on registration, this gets messy quickly in the callback implementation.

Contributing

If you want to contribute to hurler you should fork, implement your change, open a pull request.

If you are not sure if a feature belongs in hurler please open an issue to discuss it.

Some guidelines for contributing code: - Follow PEP8 when submitting code. - Write tests for new code and bugs. - Run tests often.

Running tests

We use py.test for our testing, installation is done through pip install pytest.

You can run the tests by running py.test in the root directory of this repository.