Expression Tutor

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Expression Reference

How to represent the different kinds of Python expressions as Expression Trees

Excavator operator at work.

The Python Expression Reference is still a work in progress and may thus contain imprecisions.

About Expression Tutor

Notional Machine

Expression Tutor is centered around a notional machine we call 'expression as trees'. In programming languages these trees are known as abstract syntax trees.

Faded Worked Examples

Expression Tutor allows you to gradually transition from worked examples to practice problems.

What to do?

Try our activities or design your own

Activity Sequences

How to use Expression Tutor to teach different concepts

Construct arbitrary trees, explain & present in class

Documentation

Language Center

Teaching programming languages with Expression Tutor

About Expression Tutor

Who? Why? How?

Photo credits

Alex Perez, Alexander Schimmeck, Curtis Thornton, Ivan Lapyrin, Kit Suman, Jeffrey Brandjes, Robert Horvick, Growtika on Unsplash.

Expression Tutor

Created by the Lugano Computing Education Research Lab in 2026.