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 callable to dynamically check and generate methods

We will now look into another familiar function named callable to check on how it can be used to perform reflection on an object.

Note

A class, method, or a function is callable in Python, while class objects or variables are not callable.

In this example, we will check whether a class is callable, and if it returns true, we will dynamically add a method to the class. To test the usage of the callable function, we will first create a coupon class and name it SimpleCoupon:

class SimpleCoupon:
    pass

Let’s check whether the preceding class is callable:

callable(SimpleCoupon)
True

In the following code, we will create a function that generates another function if called. We will create a create_coupon function that, in turn, creates a generate_coupon function or method when called:

def create_coupon( product, product_category, brand, source, expiry_date, quantity:
...