Abracadabra! Bringing the magics to xeus-python

Last year, we set ourselves to implement a visual debugger for JupyterLab. This endeavor required major developments in the JupyterLab front-end, in core-Jupyter protocols, and on the kernel side (the part of the Jupyter infrastructure responsible for executing the code).

For kernel-side development, we decided to start with the xeus-python kernel, a lightweight implementation of a Jupyter kernel for the Python programming language. Based on xeus, xeus-python has a flexible concurrency model that was required to e.g. add breakpoints while executing code.

Unfortunately, xeus-python did not provide all ipykernel features (magics, Matplotlib support, etc.). Furthermore, many notebooks depend on IPython, as they import it explicitely or make use of the IPython configuration system.

Today, we are proud to announce that xeus-python supports 100% of the IPython magics! This was achieved by leveraging the core IPython package. This is getting us closer to feature parity with ipykernel.

Magics

xeus-python now supports all magics that IPython provides and even user-defined magics!

Support for builtin IPython magics and user-defined magics

Matplotlib

Most Matplotlib back-ends are now supported by xeus-python, allowing you to show static plots with the inline back-end or interactive plots with ipympl in your Notebook:

Matplotlib inline back-end and ipympl interactive back-end

Extending

IPython has a rich configuration system that you can tweak in order to get an enhanced Notebook experience. Xeus-python now supports any configuration you setup for IPython:

Automatically import NumPy in the IPython settings

Visual Debugging

The latest JupyterLab version introduced a visual debugger in its interface. xeus-python was the first Jupyter kernel to add support for it!

Stepping into Python code in JupyterLab with the visual debugger

xeus-python is not the only Jupyter kernel that supports debugging anymore: xeus-robot is a xeus-based Jupyter kernel for the RobotFramework language that supports the JupyterLab visual debugger.

Try it online

Thanks to MyBinder, you can try it out without the need of installing anything on your computer. Just follow this link:

Installation

You can install the latest xeus-python version using mamba or conda:

mamba install xeus-python -c conda-forge

Or

conda install xeus-python -c conda-forge

You can also compile it yourself, instructions can be found in the repository:
https://github.com/jupyter-xeus/xeus-python

Acknowledgments

My work on xeus and xeus-python at QuantStack was funded by Bloomberg.

About the Author

My name is Martin Renou, I am a Scientific Software Engineer at QuantStack. Before joining QuantStack, I studied at the aerospace engineering school SUPAERO in Toulouse, France. I also worked at Logilab in Paris, France and Enthought in Cambridge, UK. As an open-source developer at QuantStack, I work on a variety of projects, from xtensor and xeus-python in C++ to ipyleaflet and bqplot in Python and JavaScript/TypeScript.