Andrey Shchekin made a good point when he commented on my post about graphical DSL:
I do not use DSLs that are purely graphical. But talking about documentation, I think it is very useful to have a graphical _representation_ for some DSLs that is synchronized with (or generated from) the DSL itself.
For example, any workflows or dataflows (think Rhino ETL) are much easier to see at a glance on visual surface. Editing them on visual surface is also an option, but not a requirement.
I certainly am a believer that a DSL should be mostly declarative, and indeed, taking Rhino ETL as an example, it is something that can have a visual representation.
The only remaining question is how?
Long ago there was Lithium and Netron projects, which were good for building the kind of UI that a DSL is composed of. Those have gone commercial now, and while I can probably find the originals somewhere, that is not a very promising concept. There is always the Visual Studio DSL toolkit, but I have a strong suspicion that I would not like it (COM involved), and anyway, I want to do it externally to Visual Studio.
Anyone familiar with useful libraries that can make it happen? Ideally, it would allow me to generate UI similar to the class designer. It should also be simple, but I am not sure how to really quantify that.