موضوع قبلی

16. چالش‌های بیشتر در فصل برداشت

موضوع بعدی

1. The dot notation

Introduction to OOP in Python with Reeborg

As you know, Reeborg is in poor shape. It can only turn to its left, its compass is broken as it can only be used to determine whether or not Reeborg is facing North. Reeborg cannot turn its head left, so it cannot find out if there is a wall to its left without turning its entire body. Finally, it leaks oil which is bad for itself and the environment.

Using the power of Object-Oriented Programming, you will learn how to fix Reeborg and how to give it additional capabilities.

For advanced programmers!

If you are not a beginner Python programmer and are experimenting on your own based on what you already know, you may find that some advanced but valid Python code you write will occasionally raise some unexpected exceptions. The reason is that most of the code powering Reeborg's world is written in Javascript and there's only a thin layer that has been written in Python using Brython. As a result some Javascript objects, methods or attributes are not directly available. Furthermore, animations are done by cloning and saving the world state as a JSON string; if you attempt to create your own class using some objects already present, you may unknowingly create a circular reference which will prevent the cloning and raise an exception.

I could have written the entire program in Python using Brython ... but it would have made the situation worse if I had tried to use the result to enable programmers to use Javascript or CoffeeScript as their language of choice -- which they can do now.