This book uses BASIC, which I just find quite unreadable.

I don't know of what other resources are available, but I do know I've seen some that use Matlab. I've never played with Octave much, so I don't know how compatible it is; can you just directly copy Matlab code, or do you need to do translations?

Anyhow, if there's a book that uses Matlab rather than BASIC, and could be used in Octave, that might be more readable. I would find C, C++, Python, or Rust more familiar, though.