Scoped signals, actions and guards

[zimri-leisher]

I have a suggestion for enhancing the FPP state machines that would allow users to give their SMs more well-defined structure:

• signals, actions and guards with "state-local scope"
• if we could define a signal/action/guard inside of a state, and make that signal/action/guard only visible to that state and its substates, this would allow us to define which signals/actions/guards can legally be used inside of each state
• right now, a common pattern I have is:
  
• where stepStatement is expected to raise one of the 5 signals that follow it. It would be a coding error for A) any other function to raise one of these signals and B) for this function NOT to raise one of these signals
• allowing users to define s./a./guards in a state would prevent A)
• I imagine it would look like this:
  

Originally posted by @zimri-leisher in nasa/fprime#2848 (reply in thread)