Speaking of mathematicians, they've also come up with an explanation how to model those graph based, "data flow" languages like Simulink or Blender's connected

Speaking of mathematicians, they've also come up with an explanation how to model those graph based, "data flow" languages like Simulink or Blender's connected nodes abstractly. They are all examples of diagrams in some (traced, symmetric) monoidal/cartesian category. What is missing is a programming system that isn't tackling a specific area based on that model, that is it supports polymorphism. Haskell's arrows come close, it is relatively easy to model cartesian closed categories in it. But something better, with graphical visualization and maybe direct manipulation would certainly desirable.