Packaging your code

Congratulations, you have now created your own adventure game in object-oriented style!

One of the benefits of writing your code in this programming style is that you can share the reusable classes you have written so that other people can use them to make their own game. If you are an educator, you might want to share them with your students, allowing them to create their own games. Alternatively, you might simply want to share your code with the world!

You have probably already used Python packages by adding an import statement at the top of your script, like this:

import random

You may be surprised to learn that you can make your classes into a package like that simply by adding a single extra file. This is only possible if you are using Python on your computer, rather than on the Trinket emulator.

First, put all of your class files into one folder. Do not include your main.py file – remember we are packaging just the reusable classes and not your finished game. Make sure the folder’s name has no spaces or capital letters – we called ours rpg. In the same folder, create a new file and save it as __init__.py, with double underscores on each side of ‘init’.

Inside this file, you need to import all of your classes in the following format:

from .filename import Classname

For example, here is the __init__.py file from my game:

from .character import Character, Enemy
from .item import Item
from .room import Room

As you can see, you can import multiple classes from the same file by separating the class names with a comma.

Navigate to the folder that contains your rpg folder and create a new Python file called main.py. Inside this file, you can import your package in this format:

import rpg

You can then refer to your classes with dot notation, so the Room class would be rpg.Room, and the Character class would be rpg.Character. Doing so lets Python know from which package the class definition is coming. You do not need to specify the package when calling methods on an object, as Python learns the class definition when you create the object.

For example, here is my main.py file:

import rpg

marc = rpg.Character("Marc", "A mystical wizard with magic powers")

marc.describe()

If other people want to to use your code, they simply need to have a folder containing your rpg package, and then they can create their own Python file and import your hard work to use in their game. If you are an educator, you might also want to package up certain bits of code that your learners can use in situations in which it is not important for them to know how the code works.