You are not limited to writing custom magic commands in Python. Several languages are supported, including R and Octave. We will look at one in particular, Cython.

Cython is a language that can be used to write C extensions for Python. The goal for Cython is to be a superset of Python, with support for optional static type declarations. The driving force behind Cython is efficiency. As a compiled language, there are performance gains to be had from running C code. The downside is that Python is much more productive in terms of programmer hours. Cython can translate Python code into compiled C code, achieving more efficient execution at runtime while retaining the programmer friendliness of Python.

The idea of turning Python into C is not new to Cython. The default, most widely used interpreter (CPython) for Python is written in C. In some sense then, running Python code means running C code, just through an interpreter. There are other Python interpreter implementations as well, including...