It was an interesting read, thank you! I somewhat disagree about the importance of incremental parsing in a structured editor. The editor is supposed to understand the data structure and be context sensitive enough to provide natural editing gestures. For example, you should be able to edit an XML document from scratch without any incremental parsing. I'm not saying that parsing (incremental or not) should not be used at all in a projectional editor, but it's just a means to an end, and there are other ways to edit a complex data structure.

BTW, I'm the author of ProjecturEd a projectional editor written in Common Lisp, see here: https://github.com/projectured/projectured

I would also like to see more research in this area, including the idea of environments that permit more than one mode of editing.

@Marina I wish for the same! A challenge is that research in this field tends to go in fits and starts. Just as someone / a group starts to get somewhere interesting, something non-research related happens that causes them to stop -- normally it's as simple as their money running out. I keep hoping that something good will happen to break that cycle!