This is Part 4 in the ‘Diary of a Flying Car Engineer’ Series
This post discusses the Event Driven Programming Paradigm.
Event Driven Programming
Event-driven programming is a programming paradigm in which the flow of the program is determined by events.
- There is a loop constantly listening to callbacks.
- For a given callback, a state transition might occur.
- Listener() Resumes.
How is Event Driven Programming different from Standard Programming paradigm?
- Event Driven is based on Events unlike a program with a fixed flow.
- It can have different possible outcomes during execution based on the interaction with environment and events that occur.
EDP in Flying Cars:
- Flights are dynamic.
- Allows response to different changes in Environment.
- Allows re-planning in real flight time.
Below, is the code for ReaderBot: A EDP based chatbot that interacts with you and opens articles that you’d like to read based on your responses.
Feel free to check the GH repository. Below, is the explanation of the key functions.
- Register Callbacks:
Maintain a local copy of responses to callbacks.
For Example, consider a callback for Self Driving Cars.
This is a callback that the Bot is expected to execute when provided an input of “SDCs”
self.register_callback("Self Driving Cars", self.respond_to_sdc)
We have to populate a local dictionary for accepted messages for the pre-defined responses, such as the SDC callback shown above.
def register_callback(self, message, callback): """ Registers a callback to a message. """ if message not in self.accepted_messages: self.accepted_messages[message] =  self.accepted_messages[message].append(callback)
Here, We’re creating a local dictionary of accepted messages for standard responses.
- Registering specific actions:
If you want to read something on Self Driving Cars, You’d expect the ReaderBot to call a SDC callback.
def respond_to_sdc(self): webbrowser.open_new("https://hackernoon.com/a-self-driving-new-year-33284e592f35")
This would open in a new tab, a post on Self Driving Cars.
Next up, is extending EDP to the Flying Car World and programming Flight Plan for an Autonomous Drone.