StateMachine< System, IDType, Message, delay_ms, do_log > Class Template Reference

State Machine :)))))) A fun fun way of controlling stateful subsystems - used in the 2023-2024 Over Under game for our overly complex intake-cata subsystem (see there for an example) The statemachine runs in a background thread and a user thread can interact with it through current_state and send_message. More...

#include <state_machine.h>

Classes
class	MaybeMessage
	MaybeMessage a message of Message type or nothing MaybeMessage m = {}; // empty MaybeMessage m = Message::EnumField1. More...
struct	State

Public Member Functions
	StateMachine (State *initial)
	Construct a state machine and immediatly start running it.
IDType	current_state () const
	retrieve the current state of the state machine. This is safe to call from external threads
void	send_message (Message msg)
	send a message to the state machine from outside

Detailed Description

template<typename System, typename IDType, typename Message, int32_t delay_ms, bool do_log = false>
class StateMachine< System, IDType, Message, delay_ms, do_log >

State Machine :)))))) A fun fun way of controlling stateful subsystems - used in the 2023-2024 Over Under game for our overly complex intake-cata subsystem (see there for an example) The statemachine runs in a background thread and a user thread can interact with it through current_state and send_message.

Designwise: the System class should hold onto any motors, feedback controllers, etc that are persistent in the system States themselves should hold any data that only that state needs. For example if a state should be exitted after a certain amount of time, it should hold a timer rather than the System holding that timer. (see Junder from 2024 for an example of this design)

Template Parameters

System	The system that this is the base class of class Thing : public StateMachine<Thing> @tparam IDType The ID enum that recognizes states. Hint hint, use anenum class`
Message	the message enum that a state or an outside can send and that states respond to
delay_ms	the delay to wait between each state processing to allow other threads to work
do_log	true if you want print statements describing incoming messages and current states. If true, it is expected that IDType and Message have a function called to_string that takes them as its only parameter and returns a std::string

Constructor & Destructor Documentation

StateMachine()

template<typename System , typename IDType , typename Message , int32_t delay_ms, bool do_log = false>

StateMachine< System, IDType, Message, delay_ms, do_log >::StateMachine ( State * initial )

inline

Construct a state machine and immediatly start running it.

Parameters

initial

the state that the machine will begin in

Member Function Documentation

current_state()

template<typename System , typename IDType , typename Message , int32_t delay_ms, bool do_log = false>

IDType StateMachine< System, IDType, Message, delay_ms, do_log >::current_state ( ) const

inline

retrieve the current state of the state machine. This is safe to call from external threads

Returns

the current state

send_message()

template<typename System , typename IDType , typename Message , int32_t delay_ms, bool do_log = false>

void StateMachine< System, IDType, Message, delay_ms, do_log >::send_message ( Message msg )

inline

send a message to the state machine from outside

Parameters

msg	the message to send This is safe to call from external threads

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The documentation for this class was generated from the following file:

• state_machine.h