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

Using isinstance to modify an object

We will now look at another built-in function named isinstance. This function is used to identify whether an object is an instance of a class. We will be implementing reflection on class objects by checking whether they are instances of a specific class and then customizing the object of the class accordingly. This example uses the same attributes (source, store, and manufacturer) as in the preceding example of the hasattr function.

To begin with, let’s create two objects for two different classes and apply the isinstance function to the objects of the classes to understand how this function can help in changing the behavior of Python objects. We will be reusing the CustomCoupon class from the preceding section and we will also be creating another SimpleCoupon class. We will then add two objects, coupon1 and coupon2, as follows:

coupon1 = CustomCoupon()
class SimpleCoupon:
    product_name = "Strawberry...