Well, a starting point would be this: https://github.com/c3d/xl/tree/master/doc. It's not finished, but it gives you a good idea.
For Tao3D, you have https://tao3d.sf.net.
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!
Do you have at hand a link where I can read more about this? Thank you in advance!