Projectional Textual Editor?

Question

1. are there any textual, projectional Editors available? How do they work especially regarding updating subtrees?
2. Are there any frameworks available for building them?
3. Do you know any papers describing their design?
4. How is this style of "parsing" called?

5. Where do I start if I want to implement a textual projectional editor by myself?

   • I would prefer using EMF / ECore, but that's optional.
   • As far as I know, xText uses unidirectional transformations from text to model, or at least replaces Elements cascading / whole subtrees instead of updating them.

Answer 1

Concrete and Jetbrains MPS. Also read Concrete: Rich, Customizable DSL Editors for the Browser

Answer 2

Grasp, a web-based platform for developing and publishing projectional editors.