The reason for writing this application was to try to show how can create managed code app uses object-oriented approach and that will run on a controller with more than limited resources.
An application written in the toit language (https://toit.io/) is a simulator of an automatically opening/closing door. The principle of operation is described by state machine, presented below:
I.e. the door can be opened, closed and attempted to be opened at the moment it closes, because opening and closing take time.
An application is a set of classes that implement the idea outlined above in the Introduction.
The class contains a container of objects of type Transition. Each state corresponds to a set of transitions from this state to other states under the influence of events.
The object of the Transition class contains a pair: state to which to transition, and an object with the ITransition interface, the 'execute'' method to be called on the transition.
This class describes the transition of the state machine from the current state to another under the influence of some event. In fact, this class is a wrapper for describing the transfer. In the constructor of the State class, the elements of the Trans object are converted into container of transitions.
The execute function without parameters. Parameters or additional attributes for execute an be in the class that implements the interface.
This abstract class implements the transition of the state machine from one state to another under the influence of the given event. If the transition is valid, then the transition's function is called when. The basic class also delegates to the inheritance class to implement several additional functions: create, publish, getStateName and getEventName. In this case, inheritance class is the DoorStateMachine class.
This class inherited from basic class BasicStateMachine, implements the logic described in the Introduction. Pay attention to the create method: in fact, this is the description of state machine. The class also contains an instance of object of type TimersEngine. This class allows to create several timers that are used by the application to simulate time delays when opening and closing a door.
Describes the behavior of an object with start and final functions. In this case, object is used in a timer. The start of the timer is accompanied by a call to the start method, the stop leads to the call of the final method.
Contains identifier and notifier. The latter implements the start and final commands of the timer.
Contains a container of timers, Allows to add, remove or start a named timer, as well as reset it by marking it as inactivated. The class contains a task (https://docs.toit.io/language/tasks) in terms of toit, which runs when there are no active timers and exits automatically when all running timers become inactive. Pay attention to two functions: run_periodically and run_periodically_in_task. They are what make the class work. These seven lines of code are not for the weak-minded the mournful-minded like me. The secret of using these functions was shared with me by Florian Loitsch (https://github.com/floitsch), one of the creators of the language, for which I am especially grateful to him.
And finally the main module, which creates the DoorStateMachine, initiates it and runs the simulation.
There are several options for performing this operation. he site toit.io ((https://toit.io/)) suggests installing and using the jag app, but I'm still using toit, which I installed two years ago. Judging by the documentation, both applications are similar. The application can be run on a computer and/or on ESP32. The result is identical.
Below are the results of running the application: command line and result.
micrcx@micrcx-desktop:~/toit_apps/door_simulation_short$ toit execute door_runner.toit
(17:08:19.637) @Closing - start
(17:08:19.637) [Start timer tC]
(17:08:19.637) [Closing] @start
(17:08:19.638) [State]->DOOR IS CLOSING
******* AFTER SLEEP 1200 *******
? Failed to get transition for event [close door] and state [DOOR IS CLOSING]
(17:08:20.838) @Opening - start
(17:08:20.839) [Opening] @start
(17:08:20.839) [State]->DOOR IS OPENING
(17:08:23.842) [Opening] @final
(17:08:23.842) @Opened - final
(17:08:23.843) [AutoClosing] @start
(17:08:23.843) [State]->DOOR IS OPENED
(17:08:26.352) [AutoClosing] @final
(17:08:26.353) @Closing - start
(17:08:26.353) [Closing] @start
(17:08:26.353) [State]->DOOR IS CLOSING
(17:08:28.357) [Closing] @final
(17:08:28.357) @Closed - final
(17:08:28.358) [State]->DOOR IS CLOSED
(17:08:28.358) [Final timer : close engine]
micrcx@micrcx-desktop:~/toit_apps/door_simulation_short$
micrcx@micrcx-desktop:~/toit_apps/door_simulation_short$ toit run -d=nuc door_runner.toit
2023-08-30T17:05:43.619668Z: <process initiated>
(19:05:43.471) @Closing - start
(19:05:43.516) [Start timer tC]
(19:05:43.545) [Closing] @start
(19:05:43.559) [State]->DOOR IS CLOSING
******* AFTER SLEEP 1200 *******
? Failed to get transition for event [close door] and state [DOOR IS CLOSING]
(19:05:44.836) @Opening - start
(19:05:44.871) [Opening] @start
(19:05:44.900) [State]->DOOR IS OPENING
(19:05:47.890) [Opening] @final
(19:05:47.907) @Opened - final
(19:05:47.938) [AutoClosing] @start
(19:05:47.969) [State]->DOOR IS OPENED
(19:05:50.450) [AutoClosing] @final
(19:05:50.476) @Closing - start
(19:05:50.507) [Closing] @start
(19:05:50.539) [State]->DOOR IS CLOSING
(19:05:52.510) [Closing] @final
(19:05:52.526) @Closed - final
(19:05:52.555) [State]->DOOR IS CLOSED
(19:05:52.590) [Final timer : close engine]
2023-08-30T17:05:53.096294Z: <process terminated - exit code: 0>