Thank you!
I was actually looking for something specific about parse trees vs S-expressions. That would be https://github.com/c3d/xl/blob/master/doc/HANDBOOK_1-syntax....
But I'm reading the whole thing now. Very interesting language! I don't see myself using it in production any time soon, but it looks like a wonderful tool for programming languages research. Thank you again!
For Tao3D, you have https://tao3d.sf.net.