[Tipewryter]

    you can use pip install -r requirements.txt

I don't see a requirements.txt file.

[bsdz]

Good spot. You can actually just run the following if you don't want to use poetry.

  pip install git+https://github.com/bsdz/calcengine.git#master

Unfortunately, this will only install the core library without the demo spreadsheet files. Even if you were to add the extras modifier "[demo]", it would only install additional dependencies and not the actual demo code. To use the demo you'll need to clone and follow instructions in my other comment.

[Tipewryter]

This outputs many pages of debug information and then dies. The error seems to be this:

    This package requires Rust >=1.41.0.