Howto:Basic OOP Programming

First, we need to define some variables:

# Define variables here to prevent them being recreated at every run of the loop() function
var power_consumption = nil;
var screen_power_consumption = nil;
var screens = nil;

Then, we need to create the class:

var screen = {
        # first, create the attributes of the screen
	name: "",
	type: "", 
	max_watts: 0,
	dim_watts: 0,
	dim_prop: "",
	power_consumption: func() { # next we have a function that measures the power consumption and returns it
		var dim_prop = me.dim_prop;
		if (getprop(me.dim_prop) != 0) { # if the screen is not off
			screen_power_consumption = (50 + (10 * getprop(dim_prop))); # y = 50 + 10d, where d = the value of the dimming property.
		} else { # if the screen is off, it consumes no power.
			screen_power_consumption = 0;
		} 
		return screen_power_consumption; # this means that when you run this function, you will get a value returned to you.
	},
	new: func(name,type,max_watts,dim_watts,dim_prop) { # finally the creator function, that creates instances of the class
		var s = {parents:[screen]};
		
		s.name = name;
		s.type = type;
		s.max_watts = max_watts;
		s.dim_watts = dim_watts;
		s.dim_prop = dim_prop;
		
		return s;
	}
};

Next, we create a new class called ELEC.

In the first part, we have a function called whenever the FDM initialization is complete: inside it, various instances of that class are created using the new() function. Then, in the second part, we have a loop function that actually does the hard work of calculating the power consumption per screen.

var ELEC = {
	init: func() { # initialization function
              # Create the instances of the screen class, and add them to a vector in order to use a foreach loop
              screens = [screen.new("DU1","LCD",60,50,"controls/lighting/DU/du1"),
			screen.new("DU2","LCD",60,50,"controls/lighting/DU/du2"),
			screen.new("DU3","LCD",60,50,"controls/lighting/DU/du3"),
			screen.new("DU4","LCD",60,50,"controls/lighting/DU/du4"),
			screen.new("DU5","LCD",60,50,"controls/lighting/DU/du5"),
			screen.new("DU6","LCD",60,50,"controls/lighting/DU/du6")]; 
        },
        loop: func() {
               foreach(var screena; screens) {  # note that we use a different variable, screena
			power_consumption = screena.power_consumption(); # call the power_consumption() for each instance of the screen class
			setprop("/systems/electrical/DU/" ~ screena.name ~ "/watts",power_consumption); # write the result to a property
	       }
        },
};

Finally, we add the updating function: the following code creates a maketimer and a setlistener that execute the loop(); and init(); functions respectively:

var systemsLoop = maketimer(0.1, func {
	systems.ELEC.loop(); # runs the loop(); function every 0.1 seconds
});

setlistener("/sim/signals/fdm-initialized", func { # listens to this property. When it changes, we then run the init loop and start the timer. 
systems.ELEC.init();
timer.start();
});

These are the basic parts of OOP. This code should be reasonable standalone, in that if you setprop some values (eg the dimming properties) it should work.