That is nothing new, it is how Native Oberon works (1987), which is based on Smaltalk (1972) works.
In Native Oberon, every module can export functions as commands that are mouse callable in the UI and take input from mouse selections, which can even be UI objects (gadgets).
Most of the mouse/keyboard interactions in Rio were already available in Native Oberon.
In Native Oberon, every module can export functions as commands that are mouse callable in the UI and take input from mouse selections, which can even be UI objects (gadgets).
Most of the mouse/keyboard interactions in Rio were already available in Native Oberon.