Firstly : cells + formulas are isomorphic to rule-based (expert) systems in that both are directed graphs (which may contain cycles, which is an error!).
Thus, just a thought experiment, it may be useful to turn the situation on it's head and say / ask : "So, this GUI, with formulas and cell references, is actually a way to visualize a rule-based system..."
Comments
Firstly : cells + formulas are isomorphic to rule-based (expert) systems in that both are directed graphs (which may contain cycles, which is an error!).
Thus, just a thought experiment, it may be useful to turn the situation on it's head and say / ask : "So, this GUI, with formulas and cell references, is actually a way to visualize a rule-based system..."