Yes, very event/message-oriented. The state machines exchange messages and process them to completion. I'm not sure who Lee is (Actor Model proper is Carl Hewitt, Gul Agha) but it's interesting that you make the connection, I agree. Erlang, the actor language that never heard of the actor model, has an FSM class that is also interesting to look at.

UML is a standardisation of a bunch of different techniques for drawing pictures about systems. Drawing pictures can be useful for thinking about things, especially if you're a visual thinker. But statecharts are really the star of the show I think, they represent something that is easier to understand as a picture (hygraph) than as code.

You might map out your functionality and see what you actually need in terms of programmatic functionality. LLMs are actually decent at creating the boilerplate if you know what you need.

Here's an example I had Claude throw together for states/substates for a door with a lock

https://mermaidchart.com/play?utm_source=mermaid_live_editor...

Wow. That's a lot of link. Here's the raw chart:

    stateDiagram-v2
    [*] --> Closed
    
    state Closed {
        [*] --> Locked
        Locked --> Unlocked: unlock / disengageBolt()
        Unlocked --> Locked: lock / engageBolt()
    }
    
    Closed --> Open: open [unlocked] / swing()
    Open --> Closed: close / checkSensors()
    
    note right of Closed
        Composite state with
        two substates
    end note
    
    note left of Open
        Simple state
    end note
    
    Locked: entry / engageBolt()
    Unlocked: entry / disengageBolt()
    Open: entry / startTimer()
    Open: exit / stopTimer()