Rude.py

Rude.py is a Python implementation of the rule-based control-flow pattern Rude.

Usage

Creating an instance

from rude import Rude
rude = Rude()

Adding a rule

rude.add_rule(app.py_found, app.pycache_pyc_found, app.pyc_found)
rude.add_rule(app.success)

add_rule accepts three arguments: the condition to check, the function to call when the result is true, and the function to call when it is false. Each argument can be a function reference, None or left empty.

The return value of conditions must be True for proceeding with the yes callback and False with the no branch. When a condition returns None, Rude exits the condition chain. In this case, the yes and no callbacks are not necessary. These conditions are usually exit points.

Checking conditions

Checking conditions based on the applied rules is triggered by calling rude.check_conditions().

rude.check_conditions(app.py_found)

This specifies the entry point in the condition chain and can be set to any valid rule condition.

See the examples for more details.

Benefits

• Rude allows for an on-demand execution of a chain of dynamic if-then-else statements - hereinafter referred to as rules.
• The control flow is easy to manage and the logic can be modified by simply changing the callbacks in the rules.
• The chain of condition checking can be exited or paused at any given point.
• The position in the rule hierarchy can be stored and the execution resumed at a later stage by setting the entry point.
• Each rule is seen as a separate and independent logical unit.
• Individual rules and groups of rules can be easily moved around.
• Rules can be generated dynamically or loaded from a datasource.
• The dispatcher makes it possible to ditch the rigid static conditional model in favour of a considerably more flexible one.