StateyMcStateMachines

state_machine.c

#include <stdio.h>

typedef struct {
  int counter;
} StateMachine;

typedef void* (State)(StateMachine*);

State*
second_State(StateMachine* state_machine)
{
  printf("Second state\n");
  // do things in state
  return NULL;
}

State*
first_state(StateMachine* state_machine)
{
  printf("First state\n");
  // do things in state
  return (State*)second_state;
}

int
main(int argc, char** argv)
{
  StateMachine state_machine = {0};
  State* runner = (State*)first_state;
  
  while (runner != NULL) {
    runner = (State*)(*runner)(&state_machine);
  }
}

state_machine.odin

package main;

import "core:fmt";

StateMachine :: struct {
	counter: i32
}

State :: proc(^StateMachine) -> proc(^StateMachine);

second :: proc(state_machine: ^StateMachine) -> State {
  	fmt.printf("second state: %d\n", state_machine.counter);

  	state_machine.counter += 1;
	return cast(State)first;
}

first :: proc(state_machine: ^StateMachine) -> State {
  	fmt.printf("first state: %d\n", state_machine.counter);

  	state_machine.counter += 1;
  	if state_machine.counter >= 5 {
  		return nil;
  	}

	return cast(State)second;
}

main :: proc() {
	state_machine := StateMachine{0};
	initial : State = cast(State)first;

	for {
		initial = cast(State)initial(&state_machine);

		if initial == nil {
			break;
		}
	}
}