Online Teaching with REPL

Written by Dominik Joe Pantůček on March 12, 2020.

As the pandemic of panic is taking over the world, the universities are forced to deliver the content to students via remote-access tools. Online teaching has been slowly gaining momentum anyway – but the focus is still mostly on emulating the in-class interaction between teachers and students. Read on to see there are other options.

The classical approach to online teaching is typically modeled like live streaming from conference talks. The speaker is streamed live alongside the presentation slides. Of course, the audio part is important. Although, to be honest, the video part is slightly creepy as most students have their cameras disabled and the teacher feels like talking to the wall. It is not like in a real class at all.

But what about some more interactive stuff?

The good thing about teaching algorithms and data structures in LISP-like[1] languages is that we have our old friend REPL[2] at hand. And if we share the REPL window with students, it is possible to do some pretty neat interactive teaching.

And the good thing about REPL is that it is rather low-resource application. We can run it on a remote server via a SSH connection and if we run the REPL session inside a terminal multiplexer like tmux[3], we can even use our regular computer for the class delivery and a dedicated machine for the online streaming and lecture handling.

And of course, it looks really cool – as cool as a terminal session can.


Hope you liked this short venture into the teacher’s life and see you next week with something more!


1. Wikipedia contributors. (2020, March 7). Lisp (programming language). In Wikipedia, The Free Encyclopedia. Retrieved 21:20, March 12, 2020, from

2. Wikipedia contributors. (2019, November 30). Read–eval–print loop. In Wikipedia, The Free Encyclopedia. Retrieved 21:20, March 12, 2020, from

3. Wikipedia contributors. (2020, March 11). Tmux. In Wikipedia, The Free Encyclopedia. Retrieved 21:21, March 12, 2020, from