[notmattlythgoe]

Originally Posted by SoftwareBug2.0

Do either of these methods allow non-linear steps? What happens in case of failure? Surely it's possible that a robot could fail to drive some distance.

Our autonomous modes were DAGs that would not only do different things but intentionally leave the robot in different states for the driver depending on what happened during autonomous.

With some forethought you can create some pretty interesting command groups. And yes you can account for failures. When you add any of the commands you can add timeouts to them. Of course, depending on what has failed to complete could effect if your auto mode is successful or not. Sometimes you might want the robot to not finish the auto mode if one step has failed.

Here is an example of non linear steps.

addSequential(new DriveStraightCommand(0.85, 60));
addSequential(new TurnToDegreeCommand(0.5, 45));
addSequential(new MoveAndShootCommand());
addSequential(new new TurnToDegreeCommand(0.5, -45));

MoveAndShootCommand:

DriveStraightCommand driveCommand = new DriveStraightCommand(0.85, 120);
addSequential(driveCommand);
addParallel(new WaitForDistanceCommand(40, driveCommand));
addSequential(new ShootCommand());
addParallel(new WaitForDistanceCommand(60, driveCommand));
addSequential(new ShootCommand());
addParallel(new WaitForDistanceCommand(80, driveCommand));
addSequential(new ShootCommand());

The DriveStraightCommand implements an interface called IProvidesCurrentDistance which will return the distance the command has currently moved. Using this interface you can pass the running command in to other commands and have access to the distance moved at a given time. The MoveAdnShootCommand will start the robot moving, then once it has reached 20, 40, and 60 inches will run a shoot command. The final TurnToDegreeCommand will run once the MoveAndShootCommand has finished.