| You keep using the term "semantic composition", which does not have any meaning for me. Take function composition, which is perhaps the best known example of composition. Let's say we have f(x) = x + 1 g(x) = x * x The composition (f o g) = g(f(x)) could be called a "semantic" composition because the result has the semantics of the two functions (it increments then doubles). So what does your use of the term actually mean? In general I feel you need more precision in your description. There is standard terminology for finite state machines and for programming languages that I think you could use. Take, for example, your statement "all require two state parameters". I think these are not value level parameters, but type level parameters. This is an important difference, and you should mention it. Going back to FSMs, there are several ways you can encode a FSM in a typed programming language. For example: 1. A FSM is a type constructor parameterized by the type of states. This means the FSM cannot transition to states that are not of the correct type, but it does not otherwise constrain transitions. 2. States themselves are type constructors parameterized by the type of states they can transition to. This adds more constraints (and requires more complex types) than the approach above. Do you see the difference between these and hence the need for clarity and precision in descriptions? |
As for why semantic composition is used, the following example may be instructive：
yes_or_no(exit,a) This means confirm once before exiting
yes_or_no(yes_or_no(exit,a),a) Confirm twice before exiting
yes_or_no(yes_or_no(yes_or_no(exit,a),a),a) Confirm three times before exiting
This is very similar to the composition you describe.
This is the actual code: https://github.com/sdzx-1/polystate-examples/blob/fecaffb5b7...
If there is no name for this way of using state machines, then semantic composition seems appropriate.
Exceptionally, combining two states in a polystate may actually be combining two small state machines, and I think nested selects are sufficient to illustrate this.
https://github.com/sdzx-1/ray-game/blob/9646bc3c0f1c11314aaf...
How do you understand such behavior?