"The reactive model we use is known as object-oriented reactive programming (using a 'push' model), which is both simple to understand and close to spreadsheet's model (i.e. Excel formulas)."
That they've managed to make this work in the language as a whole and not just the GUI is quite wonderful!
Reactive programming is an elegant and powerful feature for a modern language. Great achievement ! The idea to make it available also in non-graphical apps is very interesting.