[sweetsocks21]

I don't know of any generic editor that can take a current (popular) language and do that. There is however a lot going on in this space, and I'll list some examples. Most are about editing the tree structure better, but some do branch out a bit more to the graph idea.

https://docs.darklang.com/structured-editing

https://hazel.org/

http://lighttable.com/

Emacs has some structural editing plugins like ParEdit

Many graph/node based editors like Blender shaders (3D), Reaktor (music)

https://www.unisonweb.org/ (this has some of the function versioning ideas)

https://enso.org/

Smalltalk

There's many many more, these are just some I remembered off the top of my head.

[parhamn]

I appreciate the links!