Obviously to each their own, but I find almost all attempts to use anything other than mathematics a needless abstraction for the most part. Being able to poke and prod is useful, but if you do the exercises you shouldn't need to for the most part. Tensor Indices are a bit tricky at first but most notation has evolved for a fairly obvious reason.
Complaining about mathematical notation is quite common on HN, but realistically it's by far and away the easiest part of learning physics (and that's not including gasp actually doing experiments properly). If you aren't planning on doing research I guess it doesn't matter but it's worth keeping in mind that if you learn everything via Scheme or what have you, you may end up in Rome doing as the greeks do.
As someone coming from the physics side of things, I was about to post a similar comment myself. However, what the commenter is trying to do actually provides value in a way most physicists haven't experienced. I agree it'll be hard to get far if you keep avoiding mathematics, but I also think that if a physicist can't program it in a way this person can, then that is indicating a deficiency in the physicist. And I don't mean that to emphasize the programming aspect, but more that it's easy to find physicists who become good at doing the math but not so good at the actual physics, and get by merely with mathematical manipulations.
I'm not avoiding mathematics. I used to be a mathematician. The math is the whole point.
In the mechanics library that comes with the book (which I'm building on in my own work), functions can take either numerical or symbolic values. If you have a computation involving symbolic values, you can manipulate it just like you would with pencil and paper (except you can operate at a higher level of abstraction, never get writer's cramp, and never have to laboriously recopy line after line of symbols to make sure you got the right number of minus signs). If, as so often happens, you find yourself up against an intractable integral, you pass the whole thing to a numerical solver and get a number back right away. With enough calculations you can build up a qualitative understanding of the system's behavior. My understanding is that this is what mechanics people do all day, but not how mechanics is taught to newcomers.
Complaining about mathematical notation is quite common on HN, but realistically it's by far and away the easiest part of learning physics (and that's not including gasp actually doing experiments properly). If you aren't planning on doing research I guess it doesn't matter but it's worth keeping in mind that if you learn everything via Scheme or what have you, you may end up in Rome doing as the greeks do.
Cool project nonetheless.