Allow on_state() functions

[Thelmos]

Allow states to have a on_state() function that will run while in that state.

Main program loop will need a call to run_machine() to resolve than on_state() calls and resolve timed transitions.

This example shows how it would work (not tested, can contain errors):

#include <Fsm.h>

/*
 * FSM Library sample with user and timed
 * transitions.
 * Uses a button and Arduino builtin led, 
 * button can be replaced just grounding 
 * pin.
 */

// Used pins
#define LED_PIN     13
#define BUTTON_PIN  8

//Events
#define BUTTON_EVENT  0

int buttonState = 0;

/* state 1:  led off
 * state 2:  led on
 * transition from s1 to s2 when pusshing button
 * transition back from s2 to s1 after 3 seconds
 * SECOND PARAM IS NEW "on_state()" FUNCTION
 */
State state_led_off(&led_off, &check_button, null);
State state_led_on(&led_on, null, null);
Fsm fsm(&state_led_off);

// Transition functions
void led_off()
{
  digitalWrite(LED_PIN, LOW);
}

void led_on()
{
  digitalWrite(LED_PIN, HIGH);
}

void check_button()
{
  buttonState = digitalRead(buttonPin);
  if (buttonState == LOW) {
    fsm.trigger(BUTTON_EVENT);
  }
}

// standard arduino functions
void setup()
{
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUTTON_PIN, INPUT);

  fsm.add_transition(&state_led_off, &state_led_on,
                     BUTTON_EVENT, null);
  fsm.add_timed_transition(&state_led_on, &state_led_off, 3000, NULL);
}

void loop()
{
  // Call fsm run
  fsm.run_machine();
}

[Thelmos]

Created pull request #11 solving this and other issues.

[DeeJee]

I am using this version of the library but I am now getting errors:

collect2.exe*:error: ld returned 1 exit status Error creating .elf

Is there an include statement missing?

[jonblack]

@DeeJee You'll need to post some code. That error can be for multiple reasons (e.g. missing namespace). Try to reproduce the error with as small a program as possible and post it here. Also worth making sure that by "this version" you mean the code in the pull request this issue references?

[DeeJee]

Also worth making sure that by "this version" you mean the code in the pull request this issue references? Yes, I was referring to the code in the pull request.

I did what you suggested and made a tiny program with only the state machine code in it. It now compiles fine. That leaves me with a quest to find the code that caused the problem. The main version of the state machine works fine with my code but the code from the pull request does not. I think I made a mistake in my own code that I got away with.... until now.

Anyway, thank you for your tip. I should have thought about that myself :o

[DeeJee]

I currently have the state machine in use in my project. It is working fine and I an using all three functions. Thank you for creating this library.

[jonblack]

@DeeJee Are you referring to init, check and trigger as the "three functions"?

[DeeJee]

I am referring to the three functions that are passed into the State objects. I believe they are called on_enter, on_state and on_exit.