Book Image

Modular Programming with Python

By : Erik Westra
Book Image

Modular Programming with Python

By: Erik Westra

Overview of this book

Python has evolved over the years and has become the primary choice of developers in various fields. The purpose of this book is to help readers develop readable, reliable, and maintainable programs in Python. Starting with an introduction to the concept of modules and packages, this book shows how you can use these building blocks to organize a complex program into logical parts and make sure those parts are working correctly together. Using clearly written, real-world examples, this book demonstrates how you can use modular techniques to build better programs. A number of common modular programming patterns are covered, including divide-and-conquer, abstraction, encapsulation, wrappers and extensibility. You will also learn how to test your modules and packages, how to prepare your code for sharing with other people, and how to publish your modules and packages on GitHub and the Python Package Index so that other people can use them. Finally, you will learn how to use modular design techniques to be a more effective programmer.
Table of Contents (16 chapters)
Modular Programming with Python
About the Author
About the Reviewer

What makes a module reusable?

In order for a module or package to be reusable, it has to meet the following requirements:

  • It must function as a standalone unit

  • If your package is intended to be included as part of the source code for another system, you must use relative imports to load the other modules within your package

  • Any external dependencies must be clearly noted

If a module or package does not meet these three requirements, it would be very hard, if not impossible, to reuse it in other programs. Let's now take a closer look at each of these requirements in turn.

Functioning as a standalone unit

Imagine that you decide to share a module named encryption, which performs text encryption using public/private key pairs. Another programmer then copies this module into their program. When they try to use it, however, their program crashes with the following error message:

ImportError: No module named 'hash_utils'

The encryption module may have been shared, but it was dependent on another module...