Book Image

Metaprogramming with Python

By : Sulekha AloorRavi
Book Image

Metaprogramming with Python

By: Sulekha AloorRavi

Overview of this book

Effective and reusable code makes your application development process seamless and easily maintainable. With Python, you will have access to advanced metaprogramming features that you can use to build high-performing applications. The book starts by introducing you to the need and applications of metaprogramming, before navigating the fundamentals of object-oriented programming. Next, you will learn about simple decorators, work with metaclasses, and later focus on introspection and reflection. You’ll also delve into generics and typing before defining templates for algorithms. As you progress, you will understand your code using abstract syntax trees and explore method resolution order. This Python book also shows you how to create your own dynamic objects before structuring the objects through design patterns. Finally, you will learn simple code-generation techniques along with discovering best practices and eventually building your own applications. By the end of this learning journey, you’ll have acquired the skills and confidence you need to design and build reusable high-performing applications that can solve real-world problems.
Table of Contents (21 chapters)
1
Part 1: Fundamentals – Introduction to Object-Oriented Python and Metaprogramming
4
Part 2: Deep Dive – Building Blocks of Metaprogramming I
11
Part 3: Deep Dive – Building Blocks of Metaprogramming II

Checking whether an object has an attribute

While using a method or a function object defined in a framework or library by importing the library into another program, we might not always know all the attributes of the object. In such cases, we have a built-in hasattr function that can be used to introspect if a Python object has a specific attribute.

This function checks whether a given object has attributes. To test this function, we will create a class for the inventory of ABC Megamart, add the required attributes for the products stored in the inventory, and also include the price of the products along with the tax component. The price will be calculated both before and after tax for the products stored in the inventory. The following are the steps for it:

  1. We will create a class called Inventory and initiate it with the variables required for an inventory, such as product_id, product_name, date (of purchase), unit_price, quantity, unit_discount, and tax, as shown in the...