Is there a way to connect to live-running TeXmacs from Emacs? I am new to Scheme, but I like to connect to StumpWM or Nyxt via swank on Emacs. I am wondering if something similar is possible for TeXmacs.
Connecting to TeXmacs from Emacs
Well, I’m not sure what all this is about but if you want to connect TeXmacs to some external program (to drive it?) you can use scheme within TeXmacs to open a port and listen to scheme commands there. You can give a look at how the server support is coded in TeXmacs to see how to implement this kind of communication. Note also that the plugin system of TeXmacs can be used to extend the program which such kind of functionality. Browse Help->Interfacing in TeXmacs.
The Zotexmacs plugin can also give some inspiration on how to do this: