Thanks for the comments! The thing that z, readable, and wisp all lack, is that with ETNs every node has a point (x,y,z). So in addition to your source code mapping directly to your AST, it also maps to physical, geometric space (The Z axis is your program/document, the y axis is your line number, and the x axis is the column #/indent level).
So what you now have with ETNs, is the power of Lisp, now in a regular 2D/3D "structure", that you can inspect, visualize, and manipulate in new ways.
> 1. ETN uses fewer nodes. Why?
That's not compared to Lisps. Sorry, that was not clear. The paper was targeted toward a broader programming audience.
> 2. No parse errors. I have to say that I was writing in c++ recently, and the parsing wasn't an issue. And as you say, it doesn't make nonsense programs correct.
Ohayo briefly shows the power of no parse errors. Your program is parsed by little "micro-parsers", so there's no monolithic parse failure and programs can recover/autocorrect gracefully. More demonstrations here will do a better job of explaining. More to come.
> 3. No semantic diffs.
It's actually only "Semantic diffs" (not "not semantic diffs"). As opposed to syntax diffs. So "(+ 1 2)" and "(+ 1 2)" mean the same thing semantically in Clojure, for example, but git will give you a 1 line diff because of the whitespace syntax diff. In an ETN, "+ 1 2" and "+ 1 2" generally would be different, and could cause an ETN error unless the ETN allowed blank words.
4. Nothing collides. After years of going through every possible edge case, you cannot break TN. There is nothing that collides with the syntax. See for yourself. Download the library and create a TN with it's line/children set to something you think will collide. The indentation and ability to do "getTailWithChildren" takes care of all possible edge cases. (Sorry, I realize I still need to explain this better as this is a common concern and it is very surprising to people (myself included), that there are no edge cases that don't work.