Book Image

Learning Cython Programming (Second Edition) - Second Edition

By : Philip Herron
Book Image

Learning Cython Programming (Second Edition) - Second Edition

By: Philip Herron

Overview of this book

Cython is a hybrid programming language used to write C extensions for Python language. Combining the practicality of Python and speed and ease of the C language it’s an exciting language worth learning if you want to build fast applications with ease. This new edition of Learning Cython Programming shows you how to get started, taking you through the fundamentals so you can begin to experience its unique powers. You’ll find out how to get set up, before exploring the relationship between Python and Cython. You’ll also look at debugging Cython, before moving on to C++ constructs, Caveat on C++ usage, Python threading and GIL in Cython. Finally, you’ll learn object initialization and compile time, and gain a deeper insight into Python 3, which will help you not only become a confident Cython developer, but a much more fluent Python developer too.
Table of Contents (14 chapters)
Learning Cython Programming Second Edition
Credits
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Preface
Index

Overloading


Since Python supports overloading to wrap C++ overload, just list the members as normal:

cdef foobar (int)
cdef foobar (int, int)
…

Cython understands that we are in C++ mode and can handle all the type conversion as normal. It's interesting that it can also handle an operator overload easily since it is just another hook! For example, let's take the Car class again and perform some operator overriding such as the following:

namespace mynamespace {
  class Car {
    int doors;
    int wheels;
  public:
    Car ();
    ~Car ();
    Car * operator+(Car *);
    void printCar (void);
    void setWheels (int x) { wheels = x; };
    void setDoors (int x) { doors = x; };
  };
};

Remember to add these operator-overloading class members to your Cythonized class; otherwise, your Cython will throw the following error:

Invalid operand types for '+' (Car *; Car *)

The Cython declaration of the operator overload looks as you expected:

cdef extern from "cppcode.h" namespace "mynamespace":
    cppclass...